The invention discloses a design method of a lightweight structure of a palm mattress. The method comprises the following steps: layering a palm mattress to obtain mattress layers, establishing a palmmattress model, applying a human body load to the palm mattress model, carrying out stress deformation analysis, measuring the deflection value of each corresponding mattress layer in the palm mattress model, and setting the density of each mattress layer according to the deflection value change of each mattress layer to obtain the light-weight structure of the palm mattress. By adopting the method disclosed by the invention, the lightweight structural design of the palm material mattress can be guided, the palm material mattress is designed into a layered structure, and the density of the mattress is designed, so that the light weight of the mattress is realized. Through the design, the total density of the palm fiber mattress can be reduced, the use amount of mattress materials is reduced, the production cost is reduced, and the product quality can be guaranteed.