Abstract: Compared with the traditional metal materials, the composite materials have high specific strength, large modulus, good fatigue and corrosion resistance, and good thermal and electrical properties. In this paper, the composite materials are selected to carry out a layer-layer design for simply supported beams. Starting from the stress analysis of simply supported beams, the mathematical model of simply supported beams is established, according to the classical theory of composite material mechanics and the basic equation of elasticity. Then, the optimum design of the simply supported beam is carried out to determine the angle and the number of the layers of the simply supported beam, and the composite structure is constructed, the static analysis of the simply supported composite beam is carried out. Finally, the Tsai-Wu tensor criterion is used for the strength check.