Objective:To cultivate rat MSCs and explore the protective effects of MSCs on the transplanted kidney. Methods:Bone marrow was collected from SD rat by flushing femurs and tibias under sterile condition. MSCs were purified by stillness-stick cultivation in vitro. Forty wistar rats were transplanted with the left kidneys of SD rats,twenty wistar rats were infused with MSCs(Group I),not did the other twenty Wister rats(GroupⅡ). At day3,the right renal pedicle of recipients were ligated. The survival time and morphology of the transplanted kidneys were observed. Results:The survival time of Group I(15.50 ± 6.35)d was longer than that of Group Ⅱ[(6.50 ± 3.11)d,P < 0.05]. The former transplanted kidney morphology observation and function obviously surpass the latter. Conclusion:MSCs can be isolated,cultured and expanded easily in vitro,and have protective effect on the transplanted kidney in early period.