The present disclosure relates to an anti-PD-L1 antibody or an antigen-binding fragment thereof, comprising: a heavy chain variable region sequence comprising the three CDRs with the sequences of SEQ ID NOs: 2 to 4, or 6 to 8; and a light chain variable region sequence comprising the three CDRs with the sequences of SEQ ID NOs: 10 to 12, or 14 to 16. The present disclosure also relates to a pharmaceutical composition and a method for detecting expression of PD-L1 in a sample.