Abstract: Objective:To detect the specific protein expression in the urine of bladder transitional cell carcinoma (TCC), find out new tumor markers, and then explore the roles of those proteins in the pathogenesis of TCC and the value of proteomics in studying TCC. Methods:Urine samples from 24 TCC patients and the control group (including 12 postoperative patients with TCC and 12 healthy volunteers) were analyzed using surface enhanced laser desorption/ionization-time of flight-mass spectrometry (SELDI-TOF-MS) ProteinChip technology,then the proteins which had been picked out would be identified in Swiss-Prot protein database. Results:Some protein differences of proteinwere detected in the urine samples between TCC group and Control group by IMAC-Cu-3 chip, including six potential TCC biomarkers and two protein clusters. Combination of the 3438Da and 8002Da biomarkers significantly increased the sensitivity (83.3%) and the specificity (75.0%) for detecting TCC. The 3438Da biomarker had been identified as α-defensin and the 4310Da~5150Da protein cluster was identified as gp40 protein in the SWISS-PRO protein database. Conclusion:SELDI-TOF-MS ProteinChip technology can directly, quickly and expediently pick out specific TCC biomarkers from the urine of patients. It will contribute tostudy the pathogenesis of TCC and provide a valuable approach in detecting tumor marker.