【Abstract】Objective To analyze the characteristics of body fat composition and blood lipid changes in young and middleaged men with nonalcoholic fatty liver disease (NAFLD), and explore the indexes and risk factors related to NAFLD. Methods We collected exam results of adult males aged from 18 to 59 whose human body composition were analyzed at the health management center of Nanjing Gulou Hospital from January 1, 2018 to December 30, 2018. 481 ultrasound results were gathered and patients in NAFLD group were divided into 4 age groups, include 1830 years old, 3140 years old, 4150 years old and 5159 years old. 703 normal people in the same period of physical examination were selected. The results of fasting venous blood examination in the morning were analyzed. The body fat index, blood lipid, blood glucose and liver function index of the corresponding group were compared, and the risk factors of NAFLD were analyzed. Results Compared with the normal people, NAFLD in the same age group had higher BMI, BF, BFR, VFA, WC, WHR,ALT, GGT, TG, LDL and FBG, with significant difference. HDL in normal group was higher than that in NAFLD, and difference is significant. There was no significant difference in body fat index among NAFLD patients of different ages. The risk factors of NAFLD include BMI, WC, WHR, BF, BFR, VFA, ALT, GGT, TG, TC, LDL and FBG. BMI, TG, LDL, FBG, BF and WHR were independent risk factors. HDL is a protective factor.Conclusion The biochemical characteristics of NAFLD are obesity, increase of body fat, increase of visceral fat, increase of waist hip ratio, increase of fasting blood glucose, high triglyceride, high LDL and low HDL.