The invention discloses a spray type 3D printing device and method based on a composite material, and belongs to the technical field of 3D printing. The problem that many internal defects of a 3D printing product in the prior art exist is solved. Powder of an object to be printed is thoroughly mixed through a mixing system, then raw materials are fully melted through a dispersion system, a meltingsystem and a cooling system, and printing is completed by an atomizing spray head after dispersion even distribution is carried out; a heating chamber in the spray head heats and melts a wire in a molten throat pipe, complete melting of the wire is further ensured, and liquid can stably flow after melting; and in addition, air pressure in an air supply passage is accurately controlled, the size and shape of jet nozzles of the spray head are intelligently selected according to the object to be printed, one from point spray, line spray and surface spray can be selected according to the conditions, uneven temperature release in the printing process is reduced, the influence of material stress is eliminated, the warpage of time is eliminated, the defects are reduced, and the processing efficiency is improved.