The present invention relates to PCSK9 antibody, an antigen-binding fragment and the medical use thereof. Furthermore, the present invention relates to a chimeric antibody and humanized antibody comprising the CDR region of the PCSK9 antibody, and a pharmaceutical composition comprising the PCSK9 antibody and an antigen-binding fragment thereof, and the use of the same as a hypolipidemic drug. In particular, the present invention relates to the use of a humanized PCSK9 antibody in the preparation of a drug for treating PCSK9-mediated diseases or conditions.