Abstract: Multiple etiological factors are integrally involved in the development of hepatitis B virus( HBV) infection. Interleukin- 10( IL-10) is an essential cytokine of immune regulation,and IL- 10 gene promoter polymorphism affects its mRNA transcription and serum level.IL- 10 is related to the prognosis of HBV infection. This review briefly discusses the association of IL- 10 gene polymorphism and its serum level with the prognosis of HBV infection,and summarizes the role of IL- 10,as an anti- inflammatory cytokine,in host immune function,the prognosis and progression of HBV infection,and HBV- related complications. IL- 10 gene polymorphism and its serum level are closely associated with inflammatory response after HBV infection,influence HBV clearance,and are related to the severity of HBV- related liver injury,liver cirrhosis,and hepatocellular carcinoma. The determination of IL- 10 gene and serum levels may provide a predictive marker for the prognosis of HBV infection.