Paget's disease of bone is a non-inflammatory metabolic bone disease characterized by abnormal bone remodeling,mainly manifested as bone pain,bone enlargement,bone deformity and fracture.This disease is extremely rare in China,and the main causes of its formation are still unclear.Most of the literatures believe that its occurrence is related to genetic factors and environmental factors.At pres-ent,there are no clear diagnostic criteria,which mainly rely on elevated blood alkaline phosphatase and characteristic imaging changes.In this paper,a case of Paget's disease of bone was reported,who was definitively diagnosed by combining with immunohistochemistry.By re-viewing the literature,the pathogenesis,diagnosis and treatment of the malformed osteitis were mainly introduced in order to provide refer-ence for the research,diagnosis and treatment of Paget's disease of bone.