Abstract: BHK21 cells at logarithmic phase were frozen at four densities,0.5 × 10^7～4.0 × 10^7 cells/mL.After two weeks,the cells at each density in three tubes were recovered.Their vitality was calculated,and its relationship with cell density was statistically analyzed.The above steps were repeated twice.The results showed that the density of frozen cells was related to the viability after recovery.