To observe the effects of ginsenoside Rb1 on body weight，body composition，blood lipid，skeletal muscle endurance and insulin sensitivity in obese mice，and further explore its effects on AMPK signaling pathway in skeletal muscle.Methods:8-week-old C57BL/6J mice were fed with high fat diet for 12 weeks to induce obese mice model.The obese mice were randomly divided into three groups(the model control group，the metformin group and the ginsenoside Rb1 group).The peer mice fed with normal diet was set as the normal control.The mice were administrated with corresponding drugs for 8 weeks.Body weight and food intake of the mice were measured regularly every week.Treadmill test was performed on the 3rd and 7th week，and the oral glucose tolerance test was conducted on the 4th and 8th week.Body composition of the mice was detected by NMR Animal Body Composition Analyzer on the 8th week.Four indexes of plasma lipids and free fatty acid levels were detected at the end of the study.The mRNA expressions of AMPKα and PGC-1α in skeletal muscle were examined by real-time fluorescence quantitative PCR(FQ-PCR)，and the protein expression of AMPKα，p-AMPKα and PGC-1α were detected by Western blot.Results:The body weight(since the 5th week）and food intake of the mice in the ginsenoside Rb1 group were significantly lower than those in the model control group(P<0.05）in a relatively time-dependent manner.Ginsenoside Rb1 could significantly reduce the levels of triglyceride and low density lipoprotein cholesterol，while increase that of high density lipoprotein cholesterol(P<0.05).In addition，ginsenoside Rb1 reduced serum free fatty acid levels(P<0.05).After the administration of ginsenoside Rb1 for 8 weeks，the body fat mass of obese mice was decreased and the lean mass was increased，oppositely(P<0.05).The skeletal muscle endurance(P<0.05）and the oral glucose tolerance of the obese mice were improved by ginsenoside Rb1.At the molecular level，ginsenoside Rb1 could up-regulate the mRNA and protein expression of AMPKα in skeletal muscles，and the content of p-AMPK protein was also increased significantly(P<0.05).At the same time，the mRNA and protein expression level of PGC-1α were also up-regulated，correspondingly(P<0.01).Conclusion:Ginsenoside Rb1 exerts effects on reducing body weight，decreasing blood lipid levels，improving skeletal muscle endurance and insulin sensitivity in obese mice by activating AMPK signaling pathway in skeletal muscles.