This study was aimed to investigate the imaging features of collateral circulation in Budd-Chiari syndrome (BCS) and hepatitis B related liver cirrhosis (LC) with multi-detector computed tomography (MDCT), and to discuss the value of MDCT in differential diagnosis of Budd-Chiari syndrome and hepatitis B related LC. Sixty cases of LC confirmed by medical history and laboratory examination and 15 cases of BCS proven by histopathology or ultrasonography were recruited in the present study. Morphological changes and anatomic characteristics were assessed with three dimensional (3D) vascular reconstruction of MDCT in all 75 cases. There were significantly more subjects with caudate lobe enlargement in BCS (11 cases, 73%) than in LC (5 cases, 8%). In BCS group, extrahepatic collateral circulation of ascending lumbar and azygous collateral pathways were found in 9 cases and epigastric varicose veins in 8 cases. Intrahepatic venous collaterals were documented in 12 cases combined with ascending lumbar and azygous vein collaterals in 9 cases and retroperitoneal varicose vein plexus in 6 cases. These intra- and extra-hepatic venous collaterals were not dectected in patients with LC. Morphological changes of the caudate lobe and the enhanced pattern of liver parenchyma were significantly different between patients with BCS and LC. Thus, it could be well concluded that contrast-enhanced CT scan and 3D CT angiography are very useful in differential diagnosis of BCS and LC.