The invention discloses a method of mixed production of a silicon semiconductor product and a gallium nitride product, and the method comprises the steps: 1, providing a mixed production line of the silicon semiconductor product and the gallium nitride product, wherein the mixed production line is formed by adding special production equipment of the gallium nitride product to equipment of a production line of the silicon semiconductor product; 2, carrying out the mixed production, wherein the production step of the gallium nitride product in the mixed production comprises the following substeps: 21, providing a wafer; 22, forming an epitaxial layer with gallium content on the wafer by adopting the special production equipment of the gallium nitride product; 23, after finishing all the epitaxial layers with the gallium content, forming a gallium diffusion isolation layer on the back surface of the wafer to prevent the gallium in the back surface area of the wafer from diffusing outwards. The production cost of the gallium nitride product can be reduced, and the integration of the gallium nitride product and the silicon semiconductor product can be realized.