A monoclonal antibody or a derivative thereof which can antagonize and inhibit the binding of human PD-1 antigen to its ligand: the amino acid sequences of CDR1, CDR 2 and CDR 3 in the light chain variable region of the antibody are shown in SEQ ID NO:3, SEQ ID NO: 4 and SEQ ID NO: 5, respectively, while the amino acid sequences of CDR 1, CDR 2 and CDR 3 in the heavy chain variable region are shown in SEQ ID NO: 8, SEQ ID NO: 9 and SEQ ID NO: 10, respectively. A humanization preparation process for the antibody and the amino acid sequences of the heavy chain variable region and light chain variable region of the humanized antibody.
