Normal daily bile secretion is 800~1000 ml, and the bile drained after choledochotomy is about 200~300 ml/d. If there is too much bile, the lower end of the T-tube may be obstructed. Choledochotomy and T-tube drainage is an important treatment for choledocholithiasis, which can be performed laparoscopically or openly, and after removing the stone during the operation, a T-tube is placed to drain the bile after the operation. In general, the normal amount of bile drained after surgery is about 200-300 ml/d. If there is too much bile, there may be an obstruction at the lower end of the T-tube. If the lower bile duct of the T-tube is obstructed, the bile can not be discharged normally, and all of it will be drained out of the T-tube, which will cause an increase in the amount of bile drained, and the cause needs to be found and solved in time. Care should be taken to carefully observe the amount and nature of bile drainage after placement of the T-tube.