A die-casting process method for die-cast molding of a metal in a semi-solid state, wherein a semi-solid state die-casting machine is used as a processing device and a pulper is used as a device for preparing and delivering a slurry in a semi-solid state; the method comprises the steps: spraying a mold release agent and mold clamping; melting the raw material and keeping the temperature; adding a metal modificator into the molten raw material to prepare the slurry in a semi-solid state; transferring the slurry in a semi-solid state into a mold by the pulper; die-casting, opening the mold and exporting a die-cast; removing the sprue to obtain the final die-cast. In the process method, a metal modificator is added to the liquid metal raw material during the preparation of the slurry in a semi-solid state so as to generate more crystal nuclei, so that die-cast products have better mechanical properties; by way of die-casting the slurry in a semi-solid state, during mold stripping the die-cast is low in temperature and small in deformation quantity, and the best shapes and surface smoothness of the product can be guaranteed; and the die-cast is compact interiorly with producing air holes, and the best interior structure and mechanical properties of the die-cast product are guaranteed.