The authors observed the progressive changes of the platelet activity in 25 cases of acute cholangitis severe type(ASCT)within 2 weeks of pre-and-post-operation.The results revealed that there are signficant changes of the platelet activity in ASCT.The levels of the platelet activity were proportional to the severity of disease and degree of biliary duct obstruction.Persistency of abnormality of platelet activity may predict the worse of disease and bad prognosis.The results are useful to understand the complex changes of pathophysiology in ACST,to the mechanism of multiple organic failure.