Abstract: Objective To study the method to prepare gelatin microspheres carrying rat bone marrow mesenchymal stem cells（MSC）. Methods Gelatin microspheres carrying rat bone marrow MSC were prepared using the modified emulsification technique,which were cross-linked to genipin for 12,24 and 48h respectively,and compared with those of bone marrow MSC uncross-linked to gelatin.The diameter,cross-linked degree,swelling rate,bone marrow MSC-carrying rate of gelatin microspheres were detected.Survival rate of gelatin microspheres-carrying bone marrow MSC was assayed by scanning electron microscopy with fluorescence staining. Results The diameter of gelatin microspheres did not change significantly within 24h cross-linking,which was（75±15）μm,（81.58±24.68）μm and（108.64±37.44）μm,respectively.However,the diameter of gelatin microspheres decreased to 27.88± 7.46μm after cross-linked for 48 hours（P＜0.05）.The degradation time of cross-linked gelatin microspheres was significantly longer than that of uncross-linked gelatin microspheres（P＜0.05）. Conclusion The diameter of gelatin microspheres is moderate 24h after cross-linked to genipin.The degradation time and bone marrow MSC carrying rate can meet the requirements of experiment.The gelatin microspheres-carrying MSC can survive quite well.