Due to the increase of oil price and the gradual strictness of environmental regulations, lightweight structural components for automotive become the best means to reduce oil consumption and pollution. Since interior light structural components of automotive sustain less external force, the lightweight of these components, including steering wheel frame, seat frame and instrument panel frame, is highly feasible to transform from steel to light metal in terms of engineering experiences and technologies in light metal manufacturing process at current stage. The key technology aims to integrate lightweight design, stress analysis, casting simulation, assembly and prototype testing of interior structural components. One of commercialized lightweight components is the steering wheel frame, which is originally from pieces of steel pipe and stamped steel plate to simplified shape of die casting magnesium part eventually. This results in weight reduction by 20%, parts decrease of more than 4 pieces and increase of assembly accuracy.