The rocker arm component of MG2×200/925-AWD coal mining machine in Huangling No.1 Mine was taken as the research object, and the stress distribution of rocker arm at the maximum swing arm angle position was obtained through simulation analysis, and the design of dangerous parts of rocker arm was optimized to reduce the shell thickness and rib plate height. The practice showed that the optimized design avoided stress concentration in the rocker arm structure, reduced the overall mass and realized the lightweight design.