Objective To study the multi-phase CT scanning features and diagnostic value of tuberculous mesenteric lymphadenitis. Methods A total of 35 TMLN patients treated in the departments of pediatrics, respiratory medicine and emergency of our hospital from January 2014 to October 2015 were collected for the study. The multi-phase CT scanning features of TMLN patients were analyzed retrospectively through medical records and CT imaging data, and the diagnostic value of CT scanning was analyzed by pathologic results. Results The lymphadenectasis,wall peritoneal thickening and other pathological features were shown in the mesenteric root, hepatic hilum, pancreatic head and retroperitoneal regions by the CT scanning and crown sagittal scan. There were 71.43% (25/35) of patients with lymph node lesions showing annular enhancement features in the arterial phase, portal phase and parenchymal phase in the multi-phase enhanced scan of 35 TMLN patients, which was significantly higher than the non-annular enhancement features with 28.57% (10/35, including 4 cases of uniform enhancement and 6 cases of irregular enhancement ) (P<0.05). With the delayed scan of contrast medium injection, it was convenient to observe the relationship between lesions, lymph nodes and peripheral organs, and there were 24 cases shown lymphadenectasis, spleen and stomach fluid and other lesions features in the mesangial root, among which 79.17% (19/24) cases were shown annular enhancement features and 20.83% (5/24) cases were shown homogeneous or irregular enhancement features (P<0.05). Conclusion TMLN has significant feature of annular enhancement in the lesion with multi-phase CT scanning. Enhanced delayed scan can better observe the relationship between lymph node swelling and the surrounding structure, which provides important reference for understanding the TMLN characteristics and clinical diagnosis.