Abstract: Objective To provide the experimental support for large-scale preservation of human umbilical cord mesenchymal stem cells（UC-MSC） by comparing their biological features before cryopreservation and after thawing. Methods Human UC-MSC were isolated by collagenase digestion and subcultured in vitro.The third passage human UC-MSC were frozen with a controlled rate freezer and thawed 6 months after they were stored in-196 ℃ liquid nitrogen.Their biological features were compared,including morphology,growth curve,immunophenotype and multi-directional differentiation potential before cryopreservation and after thawing. Results The human UC-MSC grew in a fibroblastic morphology after thawing with a similar growth curve to that before cryopreservation.The immunophenotype of human UC-MSC highly expressed the CD73,CD90,CD105 but not the CD34,CD45,CD40,CD80,CD86,CD154,HLA-DR.Human UC-MSC could differentiate into osteocytes,adipocytes and chondrocytes under special in vitro induction conditions. Conclusion Human UC-MSC can maintain their biological features after cryopreservation and thawing.