From January 1986 to December 1987, there were 294 cases of transitional cell carcinoma of urinary bladder documented in our hospital, which 94 cases of them had complete studies of both pre-operative computed tomography (CT) and pathological staging. According to the CT pictures of carcinoma of urinary bladder, we modified the Marshall Classification and staged the tumor as ”stage B2 or less”, ”stage C”, and ”stage D”. 83 cases were correctly staged by CT, and 11 cases were not correctly staged. The total accuracy rate is 88.3%. So CT is helpful in staging of carcinoma of urinary bladder, and is also helpful in the choice of patient's treatment modalities.