It is possible to turn negative with hepatitis B surface antigen 0.1iu/ml. The normal range for Hepatitis B surface antigen is less than 0.05iu/ml and Hepatitis B surface antigen 0.1iu/ml is a very low level. If the patient has not had hepatitis B in the past, then this is the acute phase of hepatitis B infection and most infected people are able to turn negative. Relying on autoimmunity, hepatitis B surface antigen gradually turns negative and hepatitis B surface antibody turns positive. If the patient has been infected with hepatitis B in the past and the hepatitis B surface antigen is 0.1iu/ml, this situation may be related to the patient’s long-term oral antiviral drugs. Since the hepatitis B surface antigen is very low, it can be combined with interferon therapy to achieve hepatitis B surface antigen conversion. The use of interferon should be under the guidance of a liver specialist and the changes in hepatitis B surface antigen should be monitored regularly.