:This paper presents a method to obtain improved foam/pillar structural designs to help enhance occupant interior impact protection. Energy absorbing foams are used in this study with their thickness and crush strength being selected as primary design variables for optimization. The response surface techniques in the design of experiment are used in the optimization process.Head impact analyses are conducted by a CAE model with explicit, nonlinear, dynamic finite element code LS-DYNA3D. A baseline model is developed and verified by comparing the simulation results with the experimental data. Based on this model, the anticipated effects of stiffness of the pillar structure and the trim on the Head Injury Criterion (HIC) results are also assessed. The optimization approach in this study provides a comprehensive consideration of the factors which affect the HIC value. The optimal designs oan be selected from the contour plots generated from the response surface based upon the design conditions of pillar stiffness, with/without trim. Optimization results are in the Forms of foam crush strength for a given foam thickness. These results provide useful information in the design and selection of foam characteristics compatible with pillar structures for further improved head impact protection.