The invention relates to a composite tower overvoltage simulation model design method. According to a structural size and material properties of a composite material tower, a composite tower multi-wave impedance model is established; according to a ground leading-down structure, a distributed parameter model is established; a power transmission line model is established; according to a soil category, a ground resistance model is established; the models are reasonably combined according to an actual structure to finally obtain a composite tower overvoltage simulation model. The composite tower overvoltage simulation model design method disclosed by the invention namely is a method for establishing, according to the structure of the composite tower, the simulation model capable of reflecting an overvoltage characteristic of a composite material under the lightning condition, and provides the basis tower design.