Abstract： Chronic HBV infection can generally be divided into four stages according to the natural course of disease. Clinically, the determination of different natural stages of chronic HBV infection is crucial for patients to start antiviral therapy and to avoid missing the antiviral opportunity and progressing to cirrhosis. In particular, it is a challenge for clinicians to distinguish the immune control stage from the reactive stage. As a novel marker of HBV, the quantitative detection of HBV core-associated antigen (HBcrAg) is of value for the identification of the HBV infection stages. This article reviews the research progress of HBcrAg in the identification of different stages of chronic HBV infection.