To explore the relationship between the uncinate process anglesin CT scanning and the space-occupying lesions of the head of pancreas. Methods: The term uncinate angle is defined as the angle made up of the anterior side and the posterior side of the uncinate process. The uncinate angle was measured in 490 CT pictures which were divided into three groups: Group A, 20 surgically and histopathologically proven cases of space-occupying lesions in the head of pancreas, not diagnosed by CT prior to surgery; Group B, 50 cases of adenocarcinoma in the head of pancreas diagnosed both by CT and histopathology; Group C, 420 cases without presence of any pancreatic lesion. Results: In group C, the mean size of the uncinate angle in 4 levels marked from the lower border upward is 30°±9°、34°±10°、37°±10°、37°±12°、38°±14°and 25°±13°respectively. The angle in cases belonging to group A and group B is significantly wider than that of group C cases(A vs C: 90°±7°vs 47°±9°, t=31.42, P＜0.01; B vs C: 96°±16°vs 47°±9°, t=36.53, P＜0.001). Conclusions: The widening of the uncinate process angle in CT scanning is a sensitive sign suggesting space-occupying lesions in the head of pancreas.