Conjugated linoleic acid (CLA), a mixture of positional and geometric isomers of linoleic acid with conjugated double bonds, has attracted considerable attention since cis-9, trans-11-CLA (c9, t11-CLA) and trans-10, cis-12-CLA (t10, c12-CLA) have a great application potential in medicines, foods and health products based on anticancer, immune regulatory, anti-atherosclerosis, anti-obesity and antioxidant activities. In this study, Kunming mice were used as experimental subjects to evaluate the inhibitory effect of CLA (80% purity, containing 36.40% c9, t11-CLA, 36.26% t10, c12-CLA and 7.14% other CLA isomers) on the obesity of mice. The tested mice were divided into obesity model control group, normal control group and CLA treatment group, and the mice in the CLA treatment group were administered with CLA by gavage for six weeks, and then obesity indexes, such as body weight, Lee's index, total weight of fat, fatty coefficient, and total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C) in serum, fatty acid synthase (FAS) in liver and viscera of the mice, were measured. The results showed that the obesity indexes, including Lee's index, fatty coefficient, TC, TG and LDL-C, in the CLA treatment groups at various dosages were significantly lower than the obesity model control group (P © 2016, Editorial Office of Food Science. All right reserved.