In recent years,the aviation industry develop to flourish,Beside Airliner private light sport aircraft have gradually become popular,and the requirement for safety is particularly important. The application of composite materials on the aircraft has gradually replaced traditional metal materials. Many composite material aircrafts are designed to improve the structure safety of the airframe,and research on structure optimization has become more and more common. This study is expected to optimize the shape and structure of the STOL CH701 and discuss the change and benefits of its safety and performance. The fuselage appearance material is aluminum alloy 6061-T6, and the structural material is carbon fiber composite material T300/LTM45-EL. The study used ANSYS and Abaqus to simulate and analyze the shape optimization of resistance profile and topology optimization of structure. The shape optimization takes the minimization of the resistance as the objective function, while the topology optimization is based on the best strain energy under the condition of maintaining the continuous structure. The result of this study is that optimum model and compare with original model, the resistance value of the fuselage after optimization was decreased by 0.9%. After the collision, the optimized fuselage complies with the 15% safety standard of MIL-STD-1290A, and the body weight is reduced by 8.2% compared with that before optimization. The strain energy of the optimized fuselage more than the initial fuselage structure, and the absorption rate of energy is 2.7% higher than the initial fuselage.