【Abstract】 Objective To compare the clinical efficacy and safety of metformin versus pioglitazone treatment for nonalcoholic fatty liver disease (NAFLD).Methods〓Retrieved from PubMed，EMbase，Cochrane Library，CNKI，WANFANG，VIP，and CBM about metformin versus Pioglitazone in the treatment of NAFLD were collected. The time limit was from the estalishing of these database to February 2016. After data extraction and quality evaluation，Metaanalysis was performed by using Rev Man 52 statistics software.Results A total of 6 studies were included，involving 372 patients. Metaanalysis data showed that:there were no significant differences between metformin and Pioglitazone groups in terms of Alanine transaminase（ALT）,aspartate aminotransferase（AST）, Total cholesterol(TC), serum triglyceride (TG)，Homeostasis model assessment of insulin resistance(HOMAIR),the weighted mean difference(WMDs) were -005U/L（95% CI:-040，031，P=097）、029（95% CI:-246，304，P=084）、-004（95% CI:-022，014，P=068）、028（95% CI:-023，080，P=028）、-004（95% CI:-042～034，P=084）；There were no significant differences in total effective rate(RR=174，95% CI: 183～364，P=014). However, metformin can significantly reduced body mass index (BMI), the weighted mean difference (WMD) is 308 (95% CI: 094,521, P=0005).Conclusion In the aspects of improving alanine transaminase, aspartate aminotransferase, total cholesterol, serum triglyceride, Homeostasis model assessment of insulin resistance (HOMAIR) and total effective rate were similar between metformin and pioglitazone groups.However, metformin can decrease the body mass index (BMI).Due to the limited quanlity and quanlity of the included studies, the above conclusion still needs to be futher verified by performing more high quality study. Therefore, for alcoholic liver disease with obesity, we prefer metformin.