Based on the finite element method, this study investigates the structural optimization of an All-Terrain Vehicle (ATV) frame to achieve lightweight design. A three-dimensional model of the frame was established and subjected to static structural analysis under extreme load conditions, as well as modal analysis to determine its inherent vibration characteristics. The analysis results identified potential areas for improvement. An optimization design was then carried out, which successfully reduced the frame's mass while ensuring its strength and stiffness met the required standards. The results demonstrate the effectiveness of the proposed method in enhancing performance and achieving weight reduction..