Abstract: Objective To explore physical activity and its association with type 2 diabetes mellitus(T2DM)in Nanjing residents.Methods Population-based cross-sectional study was conducted on local residents older than 35 years in three urban districts and two rural counties.Results The overall prevalence of T2DM was 4.6%,and 6.9% in urban,1.5% rural area,respectively.Participants with light,moderate and vigorous-physical activity had significant lower risk of T2DM compared to inactivity population(OR=0.755,95%CI=0.570~0.974;OR=0.165,95%CI=0.105~0.260;OR=0.270,95%CI=0.146~0.499 for light,moder ate and vigorous respectively).After adjusting for possible confounding factors,adjusted odds ratio(Adj.OR)of T2DM was significantly lower in moder ate physical activit y population than in physical inactivity population(Adj1 OR=0.280,95%CI=0.162~0.484).Conclusion Moderate-intensity physical activity is associated with a significant reduction in risk for T2DM.