The T-tube is placed in the common bile duct. Since the body secretes bile every day, the T-tube can continue to drain bile until the condition improves, and then it will not continue to drain bile after the T-tube is closed (which usually takes 10 to 14 days). T-tube drainage is mostly used for bile duct stones, through the T-tube to drain part of the bile to reduce the pressure of the bile duct, but also through the drainage of bile volume and character to determine whether there is bleeding and bile duct obstruction. Usually, T-tube imaging is performed 10~14 days after the operation, and after imaging and continuing drainage for more than one day, the T-tube can be closed on a trial basis. If the patient experiences discomfort, it is necessary to continue drainage, and if the patient has no obvious discomfort, the T-tube can be closed. If the T-tube of common bile duct has been placed, it is necessary to pay attention to observe the amount and nature of bile drainage. If there is excessive bile, or turbid bile, it should be considered whether there is T-tube obstruction or stones left behind. If there is any maladaptation, feedback to the physician should be made in time, and active treatment should be carried out to avoid aggravation of the condition.