Abstract: To investigate the stress and deformation behavior of connecting rod bearing bushes under multi-factor conditions, a three-dimensional coupled finite element model of the connecting rod−bearing bush was established. Based on mesh convergence verification, the effects of interference fit, bolt preload, bush material, and bolt center distance on the average contact stress and comprehensive deformation were analyzed. The results indicate that increasing the bush material stiffness reduces the comprehensive deformation, while higher bolt preload and interference fit simultaneously increase both contact stress and deformation. In contrast, the bolt center distance shows a negative correlation with contact stress and comprehensive deformation. Furthermore, orthogonal test design and grey relational analysis were employed for multi-objective optimization, yielding the optimal parameter combination: bush elastic modulus of 170.4 GPa, interference fit of 0.040 mm, bolt preload of 55 000 N, and bolt center distance of 58 mm. Finite element simulations demonstrated that, under this combination, the bush−back contact stress decreased by approximately 5% and the comprehensive deformation decreased by more than 20% compared with those of the baseline design. The results show that reasonable parameter matching can effectively improve the stress and deformation performance of connecting rod bearing bushes and provide a reliable reference for structural optimization and engineering application.