The invention discloses a brand-new PCSK9 antibody. The PCSK9 antibody is sieved through a phage display technology, then a full-length gene sequence is obtained through a gene engineering technology, and applied to preparation of the antibody, and the prepared antibody is high in yield and short in period and is a humanized antibody. The invention further discloses an anti-tumor effect of the antihuman PCSK9 antibody, which expands the way of thinking for research on occurrence and development of tumors in the future, and lays foundations for preparing the antihuman PCSK9 antibody into monoclonal antibody medicines used for treating tumors in the later period.