Endoscopic retrograde cholangiopancreatography has been widely used in the diagnosis and treatment of biliary and pancreatic diseases. Post-ERCP complications mainly include pancreatitis, infection, bleeding, and perforation. However, post-ERCP left hepatic subcapsular hematoma is a rare and potentially life-threatening complication. A total of five cases have been reported in the literature, including one death due to bleeding from a ruptured hematoma. We report a case of post-ERCP hepatic subcapsular hematoma of the left lobe of the liver in a 29-year-old woman who was diagnosed with a left hepatic subcapsular hematoma 56 hours after ERCP and whose symptoms did not improve after conservative treatment. A CT-guided percutaneous puncture was then performed, and the drainage fluid was a dark red fluid mixed with blood and bile. On days 1, 2, 3, 4, and 5, respectively, following drainage, the drainage flow was 400 ml, 40 ml, 70 ml, 50 ml, and 30 ml.