Abstract: Objective To observe the security,efficiency and related complications of transplantation of combined allogeneic hematopoietic stem cells,cord blood and mesenchymal stem cells（MSC）. Methods Hematopoietic immunity was reconstructed in 15 patients undergoing transplantation of combined allogeneic hematopoietic stem cells,cord blood and MSC,and in 15 patients not undergoing transplantation of cord blood or MSC.Implantation level and recovery of bone marrow,and transplantation-related complications were compare（dP＜0.05）. Results In the experimental group,the average speed of re-infusing cord blood was faster with the MSC count of 1.077×10⁷/kg,and the transplantation was uneventful.The number of white blood cells and platelets was over 0.5×10⁹/L and 20×10⁹/L,respectively,during an mean recovery period of 13.07d and 13.6d,which were much more that that in control group（P＜0.05）.The incidence of severe massive chronic graft versus host disease（GVHD） was lower in experimental group than in control group（P＜0.05）.However,no statistical difference was observed in chronic GVHD,lung infection,virus infection,1-year relapse and mortality between the two groups. Conclusion A high success rate can be achieved in transplantation of combined allogeneic hematopoietic stem cells,cord blood and MSC and how to increase the 1-year survival rate of patients should be further studied.