Abstract: Provided is an afucosylated monoclonal antibody. The monoclonal antibody is a human IgG antibody and has an afucosylated sugar chain structure at a heavy-chain sugar chain binding site. Also provided are application of the monoclonal antibody in the preparation of antineoplastic drugs, and a composition containing the monoclonal antibody. Compared with a fucosylated monoclonal antibody, the provided afucosylated monoclonal antibody has higher biological activity in vitro and in vivo and can be used for developing more effective therapeutic monoclonal antibody drugs.