The present invention relates to the fields of treating autoimmune diseases and molecular immunology, and specifically, to an anti-IL-17A antibody, a pharmaceutical composition thereof, and use thereof. More specifically, the present invention relates to a monoclonal antibody or an antigen binding fragment thereof, wherein a heavy chain variable region of the monoclonal antibody comprises: HCDR1-HCDR3 with amino acid sequences set forth in SEQ ID NOs: 31-33 respectively, or HCDR1-HCDR3 with amino acid sequences set forth in SEQ ID NOs: 37-39 respectively, and a light chain variable region of the monoclonal antibody comprises: LCDR1-LCDR3 with amino acid sequences set forth in SEQ ID NO: 34, KVS, and SEQ ID NO: 36, respectively, or LCDR1-LCDR3 with amino acid sequences set forth in SEQ ID NO: 40, LVS, and SEQ ID NO: 42, respectively. Monoclonal antibodies of the present invention can specifically bind to IL-17A, specifically antagonize the binding of IL-17A to a ligand thereof, and inhibit activation of fibroblasts by IL-17A.