Whether or not to place a drainage bag after biliary stent surgery needs to be based on the obstruction situation, light obstruction may only need to put in the stent, heavy obstruction will also need a drainage tube, the specific situation needs to be analyzed. 1. Light obstruction: for patients with light obstruction, the bile ducts are usually blocked by small stones. By placing a biliary stent to open the bile ducts, the obstruction caused by stones can be relieved better, so as to make bile drainage smooth, and then there is no need to place a drainage tube. 2. Heavy obstruction: If the stone is large, or the serious obstruction caused by malignant tumor of the bile duct, and the obstruction is still obvious after surgery, then it is necessary to place a drain on top of the stent, which not only plays the role of drainage, but also monitors the patient’s recovery. Therefore, in either case, the specifics of the disease should be clarified and the examination should be perfected so as not to cause the disease to progress.