Background: This retrospective study focuses on the application of computer simulation in reconstructing severe bone defects in adult players with fibrous dysplasia. Conducted from August 2017 to December 2020, the study analyzed medical records of nine patients treated in our department. The approach involved importing image data into a computer to reconstruct models of affected limbs, enabling precise lesion location identification for curettage, bone grafting calculations, and internal fixation matching. The study included nine adult patients, suffering from either monostotic or polyostotic forms of severe fibrous dysplasia, with lesions located in the humerus, femur, and tibia. The results showed that this method can shorten surgery time, minimize intraoperative trauma, and enhance the effectiveness of bone reconstruction. The average follow-up period was 32.27 months, with the MSTS score averaging 21.2 points and Shin's imaging scoring system for bone grafting scoring an average of 13.5 and 14.3 at the 1- and 2-year post-operation marks, respectively. Despite two patients experiencing complications, this technique demonstrates promise in managing severe bone defects in adults, particularly in sports-related contexts.