The invention discloses a truss framework composite material product, and a flowing medium forming mould and a forming method thereof. The truss framework composite material product consists of a framework reinforcing material, a skin material and a filling material, wherein the framework reinforcing material is formed by fixedly connecting rods and has the profile of the product; the skin material is attached to nodes of the framework reinforcing material, which serve as an outer profile; the filling material is embedded between the rods of the framework reinforcing material in the skin material; the flowing medium forming mould of the truss framework composite material product comprises a container, a cavity, a potting device and a flowing medium; and the forming method of the truss framework composite material product comprises the steps of potting the filling material into the cavity and curing the filling material to obtain the product. In the invention, the step of manufacturingthe mould cavity is saved, so that the manufacturing cost can be greatly reduced and the reinforcement function of the framework material can be fully exerted. The size of the product can be very large and is not limited to the conventional machining equipment, the length and the number of the rods of the reinforcing material are changed, and the skin material and the reinforcing material can very easily form the new cavity, so that the upgrading speed of the product is increased.