OBJECTIVE: During the treatment of diseases such as angiocardiopathy, blood lipid abnormalities and metabolic syndrome, omega-3 unsaturated fatty acids (PUFA) can reduce plasma lipids and improve cardiovascular status, thus ameliorating disease severity. We aimed to explore the effects of PUFA supplementation in patients with non-alcoholic fatty liver disease (NAFLD). METHODS: A systematic literature search was performed during March 2016 for randomized controlled trials using PUFA or fish oil supplementation in patients with NAFLD or non-alcoholic steatohepatitis (NASH). All Randomized controlled trials were retrieved from MEDLINE and EMBASE database up to date (March 2016). A meta-analysis of key outcomes (serum level of liver enzymes and lipids) were identified in these studies. The mean difference (MD) and the corresponding 95% confidence intervals (CIs) were used as measures of effect size. RESULTS: Thirteen studies were included, consisting of 266 patients in the PUFA group and 402 cases in the control group. Serum level of alanine aminotransferase (ALT) was lower in the PUFA group than that in in the controls [MD=-9.18, 95% CI (-12.41, -5.96), P <0.00001]. However, PUFA treatment did not affect aspartate aminotransferase (AST) [MD=-5.07, 95% CI (-12.65, 2.51), P= 0.19], gamma-glutamyl transferase (GGT) [MD=-1.91, 95% CI (-4.15, 0.33), P <0.009]. CONCLUSIONS: PUFA supplementation may affects serum level of ALT and improve liver function in patients with NAFLD.