Abstract： AIM: To explore the effect on umbilical cord blood ( UCB ) hematopoietic cells of Angelica polysaccharides ( ALES ) to resist cryopreservation damage. METHODS: Cytometry was used to compare the recovery rate of UCB mononuclear cells ( MNC ) when they were separated respectively by density gradient centrifugation of Ficol1, precipitation method of gelatinum and hydroxyethy1 starch (HES) ; Cytometry, method of typan blue exclusion, colony-forming assay and flow cytometry were used to detect the bioactivity of UCB MNC after frozen 1,3,6 months; MNC were cultured with various density APS for 24 h, then frozen, one month later thawed and detected the effect of resistant cryoprescrvation damage of APS on UCB MNC with the same method. RESULTS : Both the recovery rate of method of gelatinum and HES were larger than 85%, and all higher than the one of Fieoll ( 50. 00 ±4.00 ) % ( P < 0.05 ) ; After 1,3,6 months cryoprescrvation, there were no significant difference on the recovery rate of UCB MNC, CFU-Mix,CD34~+ cells and rate of typan blue exclusion, the damage was not related with freezing time. In APS groups ( except 400 mg/L APS group decreased ), the recovery rate of UCB MNC, CFU-Mix and rate of typan blue exclusion obviously increased( P <0.05 ), but there was no significant difference on the recovery rate of CD34~+ cells. CONCLUSION: APS could enhance the resistant ability of cryopreservation damage of UCB hematopoietic cells.