To investigate the diagnostic value of magnetic resonance cholangiopancreatography (MRCP) for di-agnosing low choledochal joint and its complications. MRCP results of 29 low choledochal joint patients con-firmed were analyzed retrospectively, and then compared with those by endoscopic retrograde cholaniopancreatography (ERCP). MRCP could display clearly the location of low choledochal joint, and the patients with complications involved 4 ones with cholecystolithiasis, 5 ones with cholangiolithiasis, 15 ones with cholecystolithiasis and cholangiolithi-asis, 3 ones with Mirizz syndrome, 2 ones with pancreatitis, 1 case with carcinoma of head of pancreas after cholecystec-tomy and 1 case of Vater ampullary carcinoma. Interoperative and ERCP findings proved that MRCP could be used for the diagnosis of low choledochal joint and its complications with no missed diagnosis. MRCP can be involved for the diagnosis of low choledochal joint and its complications, and thus can be used for preoperative planning and treat-ment of the complications.