The invention provides an antibody (in particular, a humanized antibody) against hepatitis B surface antigen (HBsAg), a nucleic acid molecule encoding the same, a method for preparing the same, and a pharmaceutical composition comprising the same. The invention also provides use of the antibody and pharmaceutical composition. The antibody and pharmaceutical composition according to the invention can be used for preventing and/or treating HBV infection or a disease associated with HBV infection (such as Hepatitis B), for neutralizing HBV virulence in a subject (such as human), or for reducing the serum level of HBV DNA and/or HBsAg in a subject.