Objective To establish non-alc. fatty liver disease(NAFLD) animal model induced by high-fat diet, and to anal. the effect of high-fat feeding time for animal NAFLD formation, exploring the correlation between feeding time of high-fat diet and serum alanine aminotransferase(ALT), aspartate aminotransferase(AST), triglycerides(TG), total cholesterol(TC), high-d. lipoprotein(HDL), low d. lipoprotein(LDL), fatty liver, and fibrosis formation.Methods Before the experiment, basic blood samples were collected from 700 healthy cynomolgus monkeys, then fed with high-fat diet, some of the monkeys were sampled at 1, 2, 3, 4, 5, 6 and 7 years resp. after being fed with high-fat diet and anesthetized with ketamine hydrochloride, and the blood were collected for detection of ALT, AST, TG, TC, HDL and LDL indicators, and liver tissue biopsy was performed.Results After 2 years of high-fat feed, the serum ALT, AST, TG, TC and LDL levels of cynomolgus monkeys were significantly increased(P<0.01), and HDL level was significantly decreased(P<0.01).The feeding time of high-fat feed was significantly correlated with ALT, AST, TG, TC, liver adipose and fibrosis at the level of 0.01(bilateral)(r=0.127, 0.121, 0.246, 0.128, 0.306, 0.220), but neg. correlated with HDL(r=-0.298, P<0.05), and significantly correlated with LDL at the level of 0.05(bilateral)(r=0.081).Histopathol. showed that serious fatty degeneration and balloon-like degeneration occurred in the liver over time, fatty liver followed by hepatitis and fibrosis.Conclusion The high-fat diet can significantly increase blood lipid and liver enzyme activity indexes in cynomolgus monkeys, the liver lipid aggregation and inflammatory infiltration are obvious, indicating that high-fat diet can successfully induce NAFLD model and promote the development of NAFLD.