Abstract: Objective To localize the transplanted bone marrow mesenchymal stem cells（BMSCs） in colon of a mouse inflammatory bowel disease（IBD）model. Methods BMSCs from BALB/C male mice,cultured in bone slice culture in vitro,were transplanted into a BALB/C female mouse IBD model through the caudal vein,after marked with fluorescein CFDA SE.A control group was established.Distal colon tissue was taken on days 2,5,and 9 after transplantation.The tissue was frozen and cut into sections to observe the fluorescence distribution in BMSCs and the location of BMSCs using the sex determining gene（SRY） on Y chromosome as a marker as detected by PCR. Results Adipocytes and osteoblasts were induced by the rapid proliferation and high purity of BMSCs.Some segments of colon in IBD model became narrow with ulceration due to TNBS.Fluorescence was found in colon tissue from IBD model under fluorescence microscope.The SRY gene was detected both in TNBS-MSCs transplantation group and in control group. Conclusion Transplanted BMSCs can be localized in injured colon tissue of IBD model.