Abstract: Objective:This paper observed the effects of MGF on activation and the dose-dependent manner on proliferation of SC in vitro which increasing the number available for local repair, as well as the mechanism at the levels of molecular.Method:The primary passage SC was derived from gastrocnemius muscle and soleus muscle of the Sprague-Dawley rats (4 weeks of age, male) .The third passage SC was treated with MGF and the cell proliferation rate was measured by cell proliferation assay.The third passage SC was serum starved and treated with MGF and DMEM.The cell cycle was detected with Flow Cytometry.Result:After 48h, values of the operated groups which treated with MGF of 25ng/ml and 50ng/ml were significantly higher than that of normal control group (P<0.01) .There was no significant difference between 100ng/ml group and 200ng/ml group (P>0.05) .After 96h, there was no significant difference among the operated groups of 25ng/ml, 50ng/ml, 100ng/ml and 200ng/ml (P>0.05) .There were significant differences between the operated group and the normal control group, the proportion of the SC in G0/G1 phase of operated group treated with 25ng/ml MGF was significantly lower than that in normal control group after 24h (P<0.01) .Conclusion:MGF increases skeletal muscle SC proliferation.MGF appears to initiate skeletal muscle SC activation of 4-week-old Sprague-Dawley rats.