Objective To elevate the efficacy and safety of low molecular weiGht heparins on severe acute pancreatitis. Methods Random or controlled clinical trials literatures( CRT,CTT ) which met the inclusion criteria were collected by computer retrieval combined with manual screeninG,and the data were analyzed by Meta-analysis. Results There were 6 randomized controlled study,includinG 626 cases severe acute pancreatitis which divided into low molecular weiGht heparin Group(n=3l2)and control Group(n=3l4). There were statistical siGnificant differences between Groups in terms of the mortality rate cure rate,complication rate, operation rate,averaGe hospitalization time( P<0. 05). while the parameters of coaGulation showed no siGnificant difference between two Groups. Conclusion Conventional treatment of SAP with LMWH is superior to conventional therapy in improvinG patients'outcome and decreasinG the mortality. Initial subcutaneous therapy with the LMWH appeared to be effective and safe,which cannot lead to bleedinG tendency.