Hip arthroplasty has become a common surgical procedure in joint surgery for the treatment of fractures involving the hip joint, moderate to severe osteoarthritis, bone tumors and congenital joint dysplasia. With the continuous maturation of hip replacement technology and improvement of prosthetic materials, the stability of the artificial joint has improved greatly and the wear of the prosthesis is decreasing, but postoperative complications such as wear of the prosthesis and lining separation are inevitable due to the relative movement between prosthetic components and electrolysis and degeneration of the materials, as well as the uncomfortable location of the prosthesis. Lining separation is an extremely rare postoperative complication, and research on the mechanism of occurrence, diagnosis and treatment of lining separation is even rarer, with its diagnosis mainly focused on x-ray. This article reports a case of a patient with a separated lining and not easily diagnosed definitively, and reviews the relevant literature.