This study gave a detailed explanation of the mechanism and method for the application of the enclosed passive infraversion lavagedrainage system.In this drainage system,the rinse solution was infused into the peritoneal cavity passively rather than actively.This guarantees that the output of the solution was more than the input of the solution.It is also a safe and effective system in washing severe bileleakage and pancreatic fistula in the early stage after pancreatoduodenectomy.