Provided in the present invention are an aberrantly glycosylated integrin, AG-α3β1, and use thereof as a bladder cancer marker. Also provided in the present invention are a hybridoma cell generating an anti-AG-α3β1 monoclonal antibody, a monoclonal antibody BCMab1 secreted by the same, and use of BCMab1 in the preparation of a medicament for the treatment of bladder cancer. Also provided in the present invention is use of inhibitors of GAL3ST2 and N-acetylgalactosaminyltransferase 1 in the preparation of a medicament for the treatment of bladder cancer.