Objective: This study compares two different jawbone material assignment methods: the uniform assignment method based on composite structure modeling and the non-uniform assignment method based on empirical formulas, to simulate three different osteotomy line design schemes for centric occlusion preoperatively, in order to evaluate the biomechanical characteristics of the model. Method: Three types of jawbones were selected, CT images were obtained, and related software was combined for finite element modeling. Results: The stress distribution map obtained by the uniform assignment method shows a larger stress distribution range than the non-uniform assignment method, but the maximum stress, strain, and displacement are generally lower. For the protruding and normal types of jawbones, Scheme One shows lower maximum stress, strain, and displacement under both material assignment methods, but no clear suitable scheme was found for the retrusive type. Conclusion: The protruding and normal types of jawbones are more suitable for adopting the osteotomy line design scheme of Scheme One, and for the retrusive type, other jaw angle osteotomy plastic surgery methods may need to be considered to ensure better biomechanical characteristics. Whether choosing the osteotomy line design scheme or selecting the modeling material assignment method, it is necessary to make the final decision based on the specific analysis objectives and resource conditions.