The invention discloses a design method of composite material, comprising following steps: a, determining the mechanical property and composite mode of a resin substrate and reinforced fiber; b, determining the influence range of a technological factor on the fiber content of the composite material; c, using a homogenization numerical method to calculate the engineering elastic constant of a single layer of the composite material microcosmically; d, obtaining the engineering elastic constant of the laminating structure of the composite material macroscopically basing on the engineering elastic constant of the single layer of the composite material obtained in the step c; e, obtaining the bearing capacity of the composite material basing on the engineering elastic constant of the laminating structure obtained in the step d, and step f, judging whether the bearing capacity of the composite material obtained in the step e is accord with a design demand, and determining the optimum technological factor and structure parameter of the composite material. The method takes adequate consideration of influence of the material component and the technological factor variation on the bearing capacity of the composite material, shortens the design cycle and reduces the cost.