Objective：To investigate the influencing factor in obese patients with newly diagnosed type-2 diabetes mellitus（T2DM）. Methods：From December 2017 to June 2018，a total of 157 patients with newly diagnosed T2DM in the endocrinology department from the Fifth People’s Hospital of Chongqing，were selected and divided into the obese group（n=70） and the non-obese group（n=87） according to different cut-offs for body mass index（BMI） of 25 kg/m2 on the basis of WHO-Western Pacific diagnostic criteria for adult obesity. The routine biochemical indexes of obese patients with newly diagnosed T2DM were compared and analyzed to explore the influencing factors. Results：Age（P=0.014），high density lipoprotein cholesterol（HDL-C）（P=0.036），and total bile acid（TBA） in the obese group（P=0.010） were lower than those in the non-obese group. Spearman correlation analysis showed that the onset of obe－sity in T2DM was negatively correlated with age（r=-0.191，P=0.017） and TBA（r=-0.211，P=0.008），and positively correlated with C-reactive protein（CRP）（r=0.178，P=0.027）. Binary logistic regression analysis showed that TBA（OR=0.551，95%CI=0.317-0.957，P=0.034） decreased the risk of the onset of obese in T2DM by 44.9%. Conclusion：Bile acid may be an independent protective factor for obese patients with newly diagnosed T2DM.