Abstract: Objective To investigate the expressions and significance of microRNAs (miRNAs) in patients with non-alcoholic fatty liver disease (NAFLD). Methods There are 78 cases of patients with NAFLD (NAFLD group) and non NAFLD people 58 cases (control group) in the study. From serum total RNA, qRT-PCR method for serum miR-21, miR34a, miR-122 and miR-451 were tested, and analysis the relationship between miRNAs serum expression levels and the degree of steatosis was analyzed. Results The serum miR-145 (P = 3.290) and miR21 (P = 1.570) expression level had no significant change in two groups; the miR-451 (P = 0.0309), miRNA-122 (P = 0.0083) and miR-34 (P = 0.0032) significantly increased the expression level. NAFLD patients according to the degree of liver steatosis were divided into mild (46 cases) and severe (32 cases), the miRNA-122 (P = 0.0062) and the miRNA-34 a (P = 0.0044) expression level significantly increased with the increase of the degrees of steatosis. Conclusions Serum miR-21, miR-34a, miR-122 and miR-122 expression levels of NAFLD patients were higher than non-NAFLD people, especially in miR-34a and miR-122 can be used as a biological marker of NAFLD in the diagnosis.