Objective To determine the diagnostic value of double-phase enhancement and virtual endoscopy with multi-slice spiral CT (MSCT) on clinical staging of preoperative bladder cancer.Methods Seventy-five patients with bladder cancer diagnosed by fibercystoscope or operation. All of them were examined by double-phase enhancement and virtual endoscopy with MSCT. The images were analyzed and clinical staging were obtained. The findings of MSCT (71 cases)were compared with the post-operative histopathological results. Results There were 94 lesions to be found. The staging of MSCT: T1 26 cases,T2, 27 cases, T2b 13 cases, T3 12 cases, T4 16 cases. Histopathological results: pT1 28 cases, pT2a 24 cases, pT2b 14 cases, pT3 12 cases, pT4 16 cases. The sensitivity of preoperative staging on bladder cancer was 89.4 % (84/94) by double-phase enhancement of MSCT;the sensitivity of virtual endoscopy was 96.6% (84/87)for polyploidy tumors and 90. 9 % (10/11) for sessile lesions. When double-phase enhancement and virtual images were evaluated together, the sensitivity rate increased to 94.5%. When the tumors were confined within the bladder wall (≤T2b), the diagnostic accuracy of double-phase enhancement and virtual images was 91.2% (51/56). When the tumors had invaded the tissues and organs beyond the bladder wall (≥T3), the accuracy was 100% (28/28). Conclusion Double-phase enhancement and virtual endoscopy of MSCT is of great value in clinical staging of bladder cancer.