Successful storage of red blood cells(RBCs) by freezedrying technique has important implications in blood transfusion and clinical medicine.Glycerol is a type of permeable intracellular lyoprotective agents,which can increase the concentration of cytoplasm of the red blood cells and then enhance the possibility of glass transition during freeze-drying process.The effects of glycerol on the preservation of freeze-dried human red blood cells are investigated,0%,20% and 40% glycerol solutions are used.The results demonstrate that glycerol has remarkable effects on the cell viability.The maximum viability of red blood cells is 55.3% after pretreatment with 40% glycerol solution.The recovery of hemoglobin is 63.4%.The results provide fundamental information for longterm preservation of RBCs by freeze-drying.Osmotic fragility data show that glycerol exerts osmotic protection on RBCs during freeze-drying.The levels of superoxide dismutase(SOD) are of no significant difference from that of fresh RBCs.