Lightweight of automatic vehicle is a significant application trend, using topology optimization and magnesium alloy materials is a valuable way. This article designs a new model of automobile wheel and optimizes the structure for lightweight. Through measuring and analyzing designed model under static force, clear and useful topology optimization results were obtained. Comparing wheel performance before and after optimization, the optimized wheel structure compliance with conditions such as strength can be obtained. Considering three different materials namely magnesium alloy, aluminum alloy and steel, the stress and strain performances of each materials can be obtained by finite element analysis. The reasonable and superior magnesium alloy wheels for lightweight design were obtained. This research predicts the reliability of the optimization design, some valuable references are provided for the development of magnesium alloy wheel.