The aim of this work was to explore the method of overlay design of fiber-reinforced material for a type of launch box. With the goal of controlling the weight of the box, the composite laminates mechanical theory combining with the method of finite element analysis were used to calculate the overlay design of fiber-reinforced material. When the fiber volume content was controlled in 43.6% and the total number of glass fiber cloth laminate layers was 10, the goal of box weight control in range of (23 ± 1) kg was achieved. The method of overlay design of fiber-reinforced material could effectively ensure the weight consistency and size control requirements.