Anti-PD-1 monoclonal antibody

The invention discloses an anti-PD-1 monoclonal antibody or an antigen combined fragment thereof. The anti-PD-1 monoclonal antibody comprises a heavy-chain variable region comprising at least one of the following amino acid sequences: (1) an amino acid sequence as shown in SEQ ID NO: 1, (2) an amino acid sequence as shown in SEQ ID NO:3, (3) an amino acid sequence as shown in SEQ ID NO:5, and (4) an amino acid sequence provided with one or more amino acid conservative mutations in comparison with amino acid sequences (1) to (3). According to the anti-PD-1 monoclonal antibody or the antigen combined fragment thereof of the embodiment of the invention, PD-1 can be specifically recognized, activation and multiplication of the cell T can be promoted, expression and secretion of cell factors are regulated, and anti-tumor cells can be stimulated to generate stronger immune response.