Objective To compare the diagnostic value of multi-slice spiral CT (MSCT) enhanced scan and contrast-enhanced ultrasound (CEUS) in preoperative staging of bladder cancer. Methods 98 cases of patients with bladder cancer confirmed by surgery and pathology from January 2015 to January 2017 were retrospectively analyzed and selected for the study. All patients were given MSCT enhanced scan and contrast-enhanced ultrasound for preoperative staging. The postoperative pathological diagnosis staging was taken as the standard to compare the coincidence rate of MSCT and CEUS on the preoperative staging of bladder cancer, and the ROC curve was drawn to compare the diagnostic value of MSCT and CEUS for bladder cancer. Results The coincidence rates of preoperative stages T1~T4 and pathological results of MSCT were 85.18%, 73.91%, 83.33% and 83.33% respectively. The coincidence rates of preoperative stages T1~T4 and pathological results of CEUS were 91.30%, 86.95%, 56.66% and 8.88% respectively. There was no significant difference in the coincidence rate between MSCT and CEUS in the diagnosis of stage T1 and stage T4 bladder cancer (P>0.05). The coincidence rate of CEUS for stage T2 bladder cancer was significantly higher than that of MSCT (P<0.05). The coincidence rate of MSCT for stage T3 bladder cancer was significantly higher than that of CEUS (P<0.05). The diagnostic value of CEUS for stage T2 bladder cancer was significantly higher than that of MSCT (P<0.05), and the diagnostic value of MSCT for stage T3 bladder cancer was significantly higher than that of CEUS (P<0.05). Conclusion The diagnostic value of preoperative contrast-enhanced ultrasound for stage T2 bladder cancer is higher than that of MSCT enhanced scan, and the diagnostic value of preoperative MSCT enhanced scan is higher than that of contrast-enhanced ultrasound for stage T3 bladder cancer.