The invention discloses a kit for early diagnosis of bladder cancer and a method for preparing the kit, and relates to the field of biomedical immune analysis. The detecting kit, which is fast, sensitive, highly specific in the early diagnosis of the bladder cancer is created by detecting a tumor marker of the bladder cancer tumor marker, namely, abnormally glycosylated integrin AG-alpha3beta, in human urine by means of microplate chemiluminescence immunoassay. The kit provided by the invention has the advantages of simplicity, convenience, quickness, sensitivity, high specificity, stability and the like, can be applied to early screening of the bladder cancer in a routine examination and to tracking observation and prognostic evaluation of the bladder cancer, and can satisfy the need that the existing in-vitro diagnosis of the bladder cancer is lack in specific diagnosis method.