Objective: To explore the influence of different model scopes on acetabular stress distribution and optimal osteotomy results in preoperative planning of Bernese acetabular osteotomy, so as to provide a theoretical basis for the selection and influence of model scopes in clinical preoperative planning. Methods: Two models M1 and M2 were established for a patient with hip dysplasia according to the model range, M1 including the affected hip bone and femur, M2 including the intact pelvis and the affected femur. The contact pressure, area and distribution of acetabular cartilage in the two models were compared and analyzed under the condition of standing on one leg. Results: Compared with M1 before surgery, M2 had higher contact pressure, smaller contact area and closer distribution to the meniscus edge of acetabulum. Compared with 11 postoperative plans, M1"s contact pressure variation amplitude and optimal osteotomy Angle were all less than M2. Conclusion: In the range of the model, only preoperative analysis results of the affected hip bone and femur would underestimate the degree of stress concentration and misjudge the location of the stress concentration point, and the optimal osteotomy rotation Angle would be relatively small, which would provide a certain theoretical basis for preoperative planning and modeling of osteotomy.