Objective:To observe the changes of serum adiponectin level in patients with non-alcoholic fatty liver disease (NAFLD),and to study the correlation between the serum level of adiponectin and NAFLD. Methods: A total of 110 patients with NAFLD who were hospitalized from Feb. 2006 to Mar. 2008 were included in this study. The patients were divided into non-alcoholic steatohepatitis (NASH) group (n=52,group 1) and simple fatty liver group (n=58,group 2). Fifty-four healthy volunteers were taken as normal control (group 3). The height,weight,and body mass index (BMI) were measured in all groups. The fasting blood samples were obtained to examine serum adiponectin,TC,TG,HDL-C and LDL-C. Stepwise regression method was used to analyze relationship between the serum level of adiponectin and NAFLD. Results: The serum adiponectin and HDL-C levels in group 1 and group 2 were significantly lower than those in group 3 (P＜0.01); the levels of TC,TG,and LDL-C were significantly higher than those of group 3 (P＜0.01). The serum adiponectin in group 2 was significantly lower than that in group 1 (P＜0.05). Lower serum adiponectin and HDL-C levels (P＜0.05) and higher AST level (P＜0.01) were found in group 2 than those in simple fatty liver patients. In non-alcoholic steatohepatitis patients,serum adiponectin level was negatively correlated with the levels of TC,TG (r=-0.436,P＜0.05; r=-0.567,P＜0.01,respectively) and positively correlated with the level of HDL-C (r=0.524,P＜0.01). Conclusion: The serum adiponectin level is correlated with the severity of NAFLD patients,and examination of serum adiponectin may be helpful in understanding the status of NAFLD patients.