The objective of this study was to investigate the effect of different rehydration conditions on recovery of the lyophilized red blood cells (RBC) so as to optimize the RBC rehydration. The different conditions, including different rehydration solution, the rehydration temperature, volume change rate of the lyophilized RBC rehydrated by the vapor firstly, were studied, the recovery rate and change of physiological and biochemical properties of the rehydrated RBC were detected. The results indicated that the solution of 10% (w/v) PVP40 in PBS showed the best effect, and the RBC recovery rate increased with increasing of rehydration temperature, and the optimal temperature of rehydration was at 37 degrees C. Pre-rehydration in condition of vapor could raise the RBC recovery rate, and promote the MCV and RDW to close to index of the fresh RBC, the deformability of the rehydrated RBC was no serious as compared with RBC preserved in conventional condition, but the activity level of ATP, G-6-PD, SOD, 2, 3-DPG of the rehydrated RBC less decreased. It is concluded that the optimal rehydration conditions for lyophilized RBC are pre-rehydration in the 37 degrees C with vapor firstly, PBS + 10% (w/v) PVP40 rehydration solution and rehydration temperature at 37 degrees C, but the protection of RBC membrane needs to be furtherly studied.