Abstract: Objective To evaluate the effect of metabolic syndrome on the progression of liver fibrosis in patients diagnosed with chronic hepatitis C virus （HCV） infection. Methods A total of 186 patients infected with HCV, 109 males and 77 females, were recruited in this investigation. According to the body mass index （BMI）, blood glucose level and blood lipid level, all patients were respectively divided into two groups： BMI≥24 kg/m ² and BMI < 24 kg/m ² groups, impaired fasting glucose（IFG）/clinically diagnosed type 2 diabetes mellitus （T2DM） and normal fasting glucose groups, hyperlipidemia and non-hyperlipidemia groups. The liver function-related parameters including alanine transaminase （ALT）, aspartate transaminase （AST）, AST/ALT ratio, γ-glutamyl transpeptidase （γ-GT）, alkaline phosphatase （ALP）, adenosine deaminase （ADA）, cholinesterase, total bilirubin, albumin, fibrosis index based on the four factors （FIB-4） , acute phase reaction index （APRI）, HCV RNA quantification and alpha-fetoprotein were statistically compared between different groups. The relationship between metabolic parameters and clinical parameters was analyzed by multiple linear regression. The AST/ALT ratio, cholinesterase and serum albumin levels in the IFG and T2DM groups were significantly lower, whereas the ADA levels were remarkably higher compared with those in normal fasting glucose group （all P < 0.05）. The liver function indexes did not significantly differ between the BMI≥24 kg/m ² and BMI < 24 kg/m ² groups, hyperlipidemia and non-hyperlipidemia groups （all P > 0.05）. Multiple linear regression analysis demonstrated that the triglyceride level in HCV infected patients was significantly correlated with the FIB-4 score （\beta = 0.233, P = 0.002） and APRI （\beta = 0.409, P < 0.001）. Conclusions Chronic HCV infection complicated with impaired glucose tolerance and T2DM may affect the function of liver synthesis. If complicated with metabolic syndrome, it probably accelerates the progression of liver fibrosis.