Abstract: ob＜x＞jective To investigate the efficacy of human umbilical cord mesenchymal stem cells (hUC-MSCs) in the treatment of nude mice’s diabetic wounds , and to observe the survival, colonization and differentiation of hUC-MSCs.Methods Diabetic nude mice were induced by intraperitoneal injection of STZ, and a 1.5cm diameter wound was cut from the back of the nude mice. HUC-MSCs were treated with living cell stain CM-Dil and transplanted into the wound of nude mice. Morphological observation and calculation of wound rate; Fluorescence flux of hUC-MSCs on the wound surface of nude mice after injection 0h, 6h, 1d, 2d, 7d and 14d was measured by animal imager in vivo. The skin at the ba＜x＞se and edge of the wound of the nude mice were taken at the corresponding time points, and the distribution and survival of the transplanted cells in the skin were observed and analyzed under a fluorescence microscope. On the 14th day after injection, the heart, liver, spleen, lung, kidney, brain and other tissues of the nude mice were taken out, and the distribution of hUC-MSCs was observed under fluorescence microscope.Results Compared with the control group, hUC-MSCs could significantly promote wound healing. After the injection of transplanted hUC-MSCs, the small animal imager showed that the fluorescence of stained hUC-MSCs was concentrated around the wound surface and migrated to the ba＜x＞se of the wound surface, and the concentration was the highest 24~72h after transplantation, after which the number of cells decreased rapidly. After 14 days of transplantation, no hUC-MSCs were found to survive.Conclusion hUC-MSCs can promote wound healing in nude mice, and the local concentration of hUC-MSCs is the highest 24~72h after transplantation. However, hUC-MSCs cannot colonize and differentiate in animals for a long time.