Antibodies (especially humanized antibodies) against the hepatitis B surface antigen (HBsAg), a nucleic acid molecule encoding same, a method for preparing same, and a pharmaceutical composition containing same. The anti-HBsAg antibodies have a higher binding affinity to HBsAg at a neutral pH than at an acidic pH, thereby significantly enhancing virus clearance efficiency and prolonging virus inhibition time. The antibodies and pharmaceutical composition may be used to prevent and/or treat HBV infections or diseases related to HBV infection (such as hepatitis B) for use in neutralizing the virulence of HBV in the body of a subject (such as a human) to reduce a serum level of HBV DNA and/or HBsAg in the body of the subject, or to activate a humoral immune response of a subject (such as a person infected with chronic HBV or a patient who has chronic hepatitis B) against HBV.