Recently, the need of weight reduction has been required in automobile industry. In this paper, we aim to evaluate the composite sandwich panel to substitute original steel structure of commercial vehicle. The compressive and drum-peel tests were conducted to consider core materials and resin system of the sandwich panel. Based on the test, we decided the core reinforcement and matrix materials of the panel. As a result, the composite panel were composed of aluminum profile, glass fiber prepreg and aluminum honeycomb. We also confirmed the weight reduction ratio and structural safety compared to prior steel structure components by bending test and FEM simulation.