A decrease in hepatitis B surface antigen from 4,000 to 2,000 in 2 years is an improvement. This usually indicates that the treatment for hepatitis B is effective. Hepatitis B surface antigen refers to the protein on the surface of the hepatitis B virus and is one of the five tests for hepatitis B. The hepatitis B surface antigen can be used to determine the ability of the hepatitis B virus to proliferate. Hepatitis B surface antigen is a quantitative test that can be used to determine the ability of the hepatitis B virus to proliferate in order to determine the effectiveness of medication. When a patient’s hepatitis B surface antigen drops from 4,000 to 2,000 in 2 years, it means that the hepatitis B virus is less able to proliferate, and the patient’s treatment for hepatitis B is effective and the condition is gradually relieving. When the surface antigen of hepatitis B reaches negative, it usually suggests the clinical cure of hepatitis B. Hepatitis B patients in the course of treatment, in addition to testing the hepatitis B surface antigen, should also be tested at the same time the other four items of the five items of hepatitis B, such as hepatitis B surface antibody, e antigen, e antibody, core antibody, and liver function indexes, such as aminotransferase, bilirubin, alkaline phosphatase, etc., comprehensive judgment of the patient’s condition, in order to guide further treatment. Hepatitis B patients are advised to seek timely medical treatment and actively receive treatment to avoid delaying their condition.