【Abstract】Objective To investigate the features of gallbladder carcinoma in two-phase spiral CT, and to analysis the values of two-phase spiral CT for the differential diagnosis between gallbladder carcinoma and chronic cholecystitis. Methods The two-phase spiral CT manifestations of 30 cases of gallbladder carcinoma, proved by surgery and pathology, and 30 cases of chronic cholecystitis were analyzed. Results According to the CT findings, the gallbladder carcinoma was categorized into 3 types: intraluminal mass of gallbladder in 6 out of 30 (20.0%）， thickening of the gallbladder wall in 11 (33.7%), and mass replacing the normal gallbladder in 13(43.4%). The most common enhancement patterns of the wall in gallbladder carcinoma were hyperattenuation during the arterial phase, while isoattenuation with the adjacent hepatic parenchyma during the venous phase; or hyperattenuation during both phases. The most common enhancement pattern of the wall in chronic cholecystitis was isoattenuation during both phases, with clear hypoattenuation linear shadow in the gallbladder fossa. Other ancillary features of gallbladder carcinomas included: infiltration of the adjacent parenchyma, local lymphadenopathy and intrahepatic metastasis. Conclusion Two-phase spiral CT scan can identify the features of the gallbladder carcinoma and is helpful for the differential diagnosis of these two different disease entities.