The time duration needed for primary drying is directly related with the temperature level used during the primary drying process.The effects of shelf temperature of the drying cabinet on the lyophilization of human platelets were experimentally studied.The cell recovery rate after rehydration,the morphological and structural changes,the non apoptosis rate and the non activation rate were detected and compared with those of fresh set.The results show that when the shelf temperature is set at -30℃,the cell recovery rate after rehydration reaches (89.0±3.2)% and the MPV and PDW were (12.4±1.5)fL and (18.3±1.5)% respectively,both of which are within acceptable ranges.The non apoptosis rate of rehydrated platelets is (87.5±2.6)% and the non activation rate is (80.4±2.6)%.