Vomiting blood in liver cancer patients may be caused by varices of fundic esophageal vein, rupture of blood vessel or cancer thrombus in portal vein after liver cancer with cirrhosis, which may lead to gastrointestinal hemorrhage due to elevated portal vein pressure. 1. Liver cancer with cirrhosis: liver cancer combined with cirrhosis will easily lead to portal hypertension, thus causing varicose veins in the esophagogastric fundus and opening of collateral circulation, if the blood vessel ruptures, it will lead to gastrointestinal hemorrhage, which will cause vomiting of blood. 2. Cancer thrombus: portal vein thrombus in liver cancer will also cause portal hypertension and fundic esophageal varices, when patients eat hard food, it will easily lead to rupture of fundic esophageal varices and hemorrhage, thus vomiting blood. 3. Abnormal coagulation function: liver cancer patients’ liver function is seriously damaged, and liver is the key organ to produce coagulation-related factors, so liver cancer patients may have abnormal coagulation function, which may lead to bleeding. If patients with liver cancer vomit blood, it is recommended to consult a doctor immediately to avoid endangering their lives.