Chronic hepatitis B(CHB)is an infectious disease caused by persistent infection with the hepatitis B virus(HBV)and is highly prevalent worldwide.Non-alcoholic fatty liver disease(NAFLD)is a group of liver diseases related to metabolic abnormalities,excluding those caused by alcohol consumption or other liver injury factors.In recent years,with improvement of living standards and changes in lifestyle,the incidence of NAFLD has been increasing substantially,becoming the most common type of liver diseases in China and Western countries,and the second leading cause of liver transplantation in the West.The rising prevalence of NAFLD has also led to an increase in the incidence of NAFLD in patients with chronic HBV infection.However,there is considerable controversy both domestically and internationally regarding the relationship between these two diseases,including the disease progression,pathogenesis,impact on antiviral treatment efficacy,and prognosis of these concomitant CHB and NAFLD patients.Currently,both domestic and international guidelines lack detailed descriptions of diagnostic and treatment strategies for these conditions.This article summarizes the recent research progress in concomitant CHB and NAFLD,including epidemiology,diagnostic criteria,the impact of NAFLD on the virology of HBV infection,potential mechanisms of NAFLD-induced negative regulation of HBV,the effect of NAFLD on antiviral therapy effiicacy,and prognosis.This article aims to gain a deeper understanding of the diseases themselves and provide new insights for basic and clinical research as well as diagnostic and treatment approaches.