Clinical venous cannulation are placed in the patient’s deep veins, there are two methods of cannulation: first, called peripheral venous puncture central catheterization, also known as picc. second, direct puncture of the deep veins for deep venous cannulation, peripheral venous puncture central venous cannulation, the method is to use the guidewire, catheter puncture of the peripheral arm veins, guidewire, catheter only reaches the heart’s large veins, you can perform The catheter is left in place for chemotherapeutic drug or hypertonic drug infusion to avoid venous injury. Deep vein cannulation involves direct puncture of the subclavian vein or internal jugular vein, indwelling catheterization, using guidewire and catheter to leave the catheter in the deep vein and fix it. The catheter requires frequent care, including the care of the indwelling catheter and the care of the sealing solution.