The ability of hepatitis B surface antigen to spontaneously turn negative is the spontaneous clearance of the hepatitis B virus that occurs without treatment in people with chronic hepatitis B virus infection. It is indeed possible for this to happen, but the incidence is low. Our Guidelines for the Prevention and Treatment of Chronic Hepatitis B state that “HBsAg clearance occurs in approximately 0.5% to 1.0% per year after HBeAg serologic conversion.” In the absence of complete treatment, after 20-50 years, the body’s immune system spontaneously clears the hepatitis B virus, HBsAg naturally turns negative, anti-HBs appears, and self-healing is achieved, which is called surface antigen serologic conversion or “natural conversion” of hepatitis B surface antigen. This natural conversion rate is about 0.5% to 1.0% per year. The natural conversion of hepatitis B surface antigen is related to the following factors: ① e antigen negative, i.e.: hepatitis B “small three positive”; ② low value of surface antigen, generally <200 IU/ml; ③ low level of viral replication, generally HBV DNA <2000 IU/ml; ④ age: generally speaking, in chronic hepatitis B The first peak occurs at the age of 10 to 20 years, with a natural conversion rate of about 2.7% per year; the second peak occurs after the age of 50 years, with a natural conversion rate of up to 6.6% per year.