Objective To investigate the quality of concentrated platelet with less WBC by improved white membrane method,so as to provide the basis for preparation of the concentrated platelet in the future.Methods Testing the quality indicators of 56 cases of concentrated platelet with less white blood cells by improved white membrane method,and comparing the quality indicators of 56 cases of collected platelet at random by machine.Testing the expression rate of platelet membrane surface glycoprotein molecules CD62P and PAC-1 before and after filtering in different storage time,and comparing the expression rate of 37 cases of collected platelets at random by machine.Results The differences of quality indicators between concentrated platelet with less white blood cells by improved white membrane methods and collected platelet at random by machine were not statistically significant (P＞0.05),such as volume,platelet content,Ph,amount of RBC mixed within.But The differences of amount of WBC mixed with were statistically significant (P＜ 0.01),both of sterility tests were negative.The differences of the expression rate of platelet membrane surface glycoprotein molecules CD62P and PAC-1 during storage period within 3 days were not statistically significant (P＞0.05).Conclusion The various quality indicators of concentrated platelet with less white blood cells by improved white membrane methods attain mixed concentrated platelet and platelet national standards,and in vitro platelet activity kept well.Platelet special leucocyte filter does not cause obvious platelet activation and damage within three days of storage period of concentrated platelet in filter processing.Collected platelet by machine is being activated and damaged continuously when kept in platelet oscillation device 22±2℃ for 3 days,but activation and damage does not significantly change the platelet activity in vitro.