Objective To study the diagnostic value of three-phase multislice spiral CT contrast-enhanced scan in the diagnosis of bladder cancer. Methods A total of 69 patients who were confirmed by surgery and pathology as bladder cancer and admitted to our hospital from March 2016 to April 2018 were selected. All patients underwent CT nonenhanced scan and enhanced scan before surgery. The researcher collected the clinical and imaging data of the patients, analyzed the size, number and enhancement degree of tumor lesions in the CT scan, and judged the accuracy of CT diagnosis of tumor by comparing with postoperative pathological examination results. Results The accuracy of CT in detecting bladder cancer was up to 94.20% in comparison with the results of surgical pathology. Moreover, the tumor size, shape, number and degree of enhancement are well displayed, and the relationship between tumor and surrounding tissues and organs can be distinguished clearly. Conclusion Multislice spiral CT tri-phase enhancement scanning technology has a high detection rate in the diagnosis of bladder cancer, which is helpful for the development of therapeutic strategies. It can be selected as a routine examination method for bladder cancer.