The optimization of structural parameters of the con-rod small end of a diesel engine was presented. By means of the DOE method

a set of optimal parameters could be obtained using the maximum contact pressure and the maximum compressive stress at the supporting rib fillet as criteria

and the stress distribution on the bush as constraint. The study reveals that the thickness and fillet radius of the support rib are the main factors influencing the joint deformation compatibility of the con-rod small end. Then the results of the EHD simulation and bench test indicate that the contact pressure of the optimized structure is obviously decreased and its distribution is more even.