Abstract: According to the traditional structure design, the initial solution is always provided according to the experience, including the overall layout, material selection, structure size and manufacturing process, etc. Then do the structure analysis, and check its feasible based on mechanics analysis. In such a design program, structural analysis only serves as a safe and feasible check function. Consequently, the structure will be complicated, overweight and even unreasonable, which would waste materials and increase the difficulty of fabrication. With the rapid development of finite element analysis technology, the use of numerical simulation technology for optimal design of structure can improve the distribution of design resource and the resistance of the material, saves the material consumption and make the structure more reasonable. Based on the finite element analysis software ANSYS, the conveying frame of EP18-1 topside was modeled and simulation in the construction, transportation and loadout conditions. According to the results of calculation and analysis, the structure was optimized on the premise of guaranteeing the structural and deformation, and then do the comparative analysis.