Objective To analyse the effect of specimen storage time on platelet count in apheresis Donors,in order to choose the appropriate testing time.Methods We choose fifty healthy Unpaid Blood Donors of Platelets to test platelet count in 0,0.5,1,3,6h respectively by the blood counting instrument.Results At room temperature,the count of platelets from blood samples is relatively lower at 0 hour and the difference is significant (P ＜ 0.05).After 0.5-6 hours,the count of platelets become stabilized and not has significantly different(P＞0.05).Conclusion The count of platelets of blood samples is lower at 0 hour than 0.5-6 hours,this work suggest that the count of platelets of blood samples should be done at 0.5-6 h in order to protect platelets quality.