Objective To study the value of 18F-FDG PETCT imaging in the diagnosis of bladder cancer. Methods 34 cases of patients with suspected bladder cancer who were admitted in the department of nuclear medicine of our hospital between March 2013 and February 2015 were included in the study. Before operation, the patients were diagnosed by enhanced CT and 18F-FDG PETCT imaging respectively. The effect of 18F-FDG PETCT imaging diagnosis was retrospectively analyzed with reference to the pathological results. Results All the 34 cases were diagnosed as transitional cell carcinoma by operation and pathology. The diagnostic accuracy rates of enhanced CT and 18F-FDG PETCT imaging were 91.18% and 94.12%, respectively (P<0.05). There were 11 cases of bladder tumors with presence of pelvic lymph nodes or adjacent tissue metastasis and infiltration. The accuracy of 18F-FDG PETCT imaging diagnosis (72.73%) was significantly higher than that of the enhanced CT (27.27%) (P<0.05). Conclusions Both of 18F-FDG PETCT imaging and enhanced CT are effective methods for the clinical diagnosis of bladder cancer, but 18F-FDG PET-CT imaging is better at observing bladder tumor metastasis and adjacent tissue infiltration. It is of important reference value in guiding the clinical diagnosis and understanding of the neoplastic lesions.