To date, hepatic resection is still considered the best treatment for primary and secondary tumors of the liver, and reducing and controlling bleeding is the key to reducing mortality and postoperative complications during hepatic resection. There is a wide variety of hepatic blood flow control methods, and only the rational, correct, flexible and individualized application of these blood flow control methods in hepatic resection can achieve the purpose of reducing and controlling bleeding. The hepatic blood flow control technique is still the most commonly used hepatic blood flow blocking method, which is applicable to all kinds of hepatic resections. Its advantage is that it can completely block the hepatic artery and portal vein flow to the liver without dissecting the hepatic portal. Hepatic-tip block can be divided into two types: continuous and intermittent block. Studies have shown that intermittent liver-tip blocks are more effective than continuous blocks in tolerating ischemia in sclerotic livers and do not significantly increase the amount of bleeding. The basic consensus is that the duration of a single block in cirrhotic patients should not exceed 15-20 min, and if time is not enough, the block can be repeated after 5 min. Man et al [1] reported that the total block time of 120 min can be tolerated by cycling up to 6 times. In recent years, it has been shown that ischemic preconditioning before block can help to reduce liver ischemia-reperfusion injury, i.e., block for 5 min to allow the liver to adapt, and then block for 5 min to start liver resection. Further studies on the optimal time interval between preconditioning and interruption are still underway. To avoid whole liver ischemia-reperfusion injury caused by the Pringle method, Makuuchi et al. reported in 1987 the hemihepatic inflow blocking method, which selectively blocks the inflow to the left or right hepatic hemisphere, so that the healthy side of the liver is not worried about ischemia, but the disadvantage is that continuous bleeding occurs in the unblocked hepatic plane when the liver is dissected. The common method is to dissect the portal trunk and hepatic artery on the diseased side at the first hepatic portal and block them, where a clear demarcation line can be seen at the interface between the left and right hemi-hepatic. If partial hepatectomy is performed, intermittent or continuous hepatic flow can be blocked, and Makuuchi uses a 30-minute block and a 5-minute recurrent block. Many scholars have reported that continuous blockade for more than 90 min is also safe. In 2001, Horgan et al [3] reported the half-Pringle method (half-Pringle), in which the hepatic bifurcation is separated outside the Glission sheath and the hepatic entry flow to the diseased side is blocked with a renal-tip clamp to complete hepatectomy. We use a method similar to Horgan’s, in which the hemihepatic block is performed in the gap outside the Glission sheath at the bifurcation of the hepatic hilum with a long curved vascular forceps with an 8-gauge catheter tightened, which has the advantage of not dissecting the hepatic hilum and making full use of the natural gap at the hepatic hilum, reducing surgical injury and operative time. For tumors located in the middle lobe of the liver or central type, we also adopt the method of blocking the left and right hemihepatic blood flow separately in order to reduce the ischemic time of the whole liver and prevent intraoperative visceral stasis and hemodynamic changes. When performing segmental resection, precise segmental blood flow control can be performed according to the principle of blood supply to the Cauianud segment. The hepatic artery on the diseased side is dissected at the first hepatic hilar and a blocking band is prepositioned; then the portal branch of the segment is located using intraoperative ultrasound, and a balloon catheter is placed under ultrasound guidance to block the portal flow of the branch, and then the branch of the hepatic artery is blocked to reveal a clear segmental demarcation. This method can be used in cases where the tumor is located in one liver segment and the liver function is poor. 2.Hepatic vein flow control technique When resecting tumors involving the second hepatic hilar region, there is a risk of hemorrhage or even air embolism due to tearing of the hepatic vein, and intraoperative compression may also cause tumor cells to be shed and metastasize along the hepatic vein. Although the classical technique of total hepatic flow block can avoid the above complications, it may cause systemic hemodynamic disturbances due to the simultaneous blockage of the inferior vena cava. In contrast, the hepatic vein block technique not only safely manages hepatic vein injury but also reduces the complications associated with inferior vena cava block. The basic method: ① reveal the suprahepatic vein trap in the second hepatic portal; ② dissect the root of the right hepatic vein at the right venous ligament, separate it with a vascular clamp and pass it through the vein trap to introduce the right hepatic vein blocking band; ③ dissect the gap between the caudate lobe Spiegel lobe and the left outer lobe of the liver, pass the vascular clamp from the vein trap to this gap, and introduce the common trunk blocking band of the middle and left hepatic veins. It should be noted that the middle and left hepatic veins sometimes do not form a common trunk and should be accurately determined by imaging before surgery. The hepatic vein flow control technique can be used in combination with Pringle’s method or hemihepatic flow blocking technique for different sites of tumor, respectively. Bilateral hepatic vein trunk block combined with Pringle method is an improved method for whole liver flow control [5]. Compared with the traditional method of total hepatic flow control by blocking the inferior vena cava, this method has the advantage of less systemic hemodynamic impact and allows interstitial blockade with longer blocking time frame. In most cases, this improved method can essentially replace the traditional whole liver flow blocking technique. Additional hepatic venous blockade of the main hepatic vein on the diseased side of the liver can further reduce hepatic wound hemorrhage due to hepatic venous return when hemihepatic inflow is blocked. Chen Xiaoping et al. reported 185 cases of hemihepatic and hepatic segmental resection without dissecting the portal preligation of the entry and exit vessels of the diseased side of the liver. Preoperative CT examination, intraoperative localization with ultrasound, and direct blockade of the affected hepatic Glison system and main hepatic vein flow via the liver parenchyma with vascular forceps resulted in a significant reduction in intraoperative bleeding and greatly shortened the total operative time. We usually use the hemihepatic Pringle method in combination with unilateral hepatic trunk block to achieve complete hepatic flow blockage. 3.Inferior vena cava flow control and total hepatic flow blocking technique Total hepatic flow blocking means blocking both incoming and outgoing hepatic blood flow, so that the liver is completely bloodless for hepatectomy, which is suitable for cases where the tumor is adjacent to the second and third hepatic hilum, difficult to be resected by conventional methods or the liver tumor is combined with hepatic vein and inferior vena cava thrombosis. The more commonly used procedure is the hepatic flow isolation at room temperature reported by Huguet et al [7] in 1978, in which the first hepatic hilar, subhepatic, and inferior and superior hepatic vena cava are sequentially blocked, followed by hepatic resection, with the opening sequence reversed from the block. Although the normal liver can tolerate whole hepatic flow blockade for more than 60 min at room temperature, the blocked inferior vena cava has a greater impact on systemic hemodynamics and the postoperative complication rate is about 2 or 5 times higher than that of the Pringle method. However, this method still has an irreplaceable role in the management of the posterior inferior vena cava and the third hepatic portal. Usually, when dealing with tumors in special sites, such as central tumors located in the second hepatic hilar, hepatic caudate lobe tumors, where there is a potential risk of intraoperative injury to the main hepatic vein or the short hepatic vein, pre-positioned blocking bands can be placed in the suprahepatic and infrahepatic inferior vena cava, and if necessary, total hepatic blood flow block is performed. This allows the operator to easily repair the breach, ligate the short hepatic vein, or resect and repair the lateral wall of the inferior vena cava invaded by the tumor. Some other methods of total hepatic flow block at low temperature, as well as the addition of extracorporeal venous diversion to total hepatic flow block at room temperature, are rarely used due to their narrow indications, so they will not be introduced here.