To find out the appropriate negative pressure for abdominal drainage and apply it to the postoperative abdominal drainage of patient with acute pancreatitis are reported.Abdominal tube was inserted to rabbit for negative pressure drainage monitoring and another tube was cuserted into the abdomen for continuous normal saline instillation.The recollections of drainage fluid under different negative pressure were measured.The results showed that the fluid depletion rate(70%)of the low negative pressure group(1.5 kPa)was higeher than that other in 3 groups(negative pressure 0 kPa,5 kPa and 15 kPa)(P<0.01).With this continuous low negative pressure drainage in 20 patients after severe pancreatitis operation,we found that this method have more advantages of reducing complication,promoting recovery and reducing death rate.