Provided are an anti-4-1BB antibody, an antigen-binding fragment thereof and medical use thereof. Further, provided are a chimeric antibody and a humanized antibody comprising a CDR region of the anti-4-1BB antibody, as well as a pharmaceutical composition comprising a human anti-4-1BB antibody or an antigen-binding fragments thereof, and use thereof as anti-cancer medicaments. In particular, provided is use of a humanized anti-4-1BB antibody in the preparation of a medicament for the treatment of diseases or conditions mediated by 4-1BB.