The invention relates to a method for preparing a silk screen printing composite plate, which comprises the following steps: firstly, setting the tensile force of a polyester silk screen, and adhering the polyester silk screen to a provisional frame directly; secondly, adhering a protective adhesive tape to the polyester silk screen, adhering a metal gauze screen to the polyester silk screen with an adhesive, tearing out the protective adhesive tape, and separating the unnecessary internal polyester silk screen to prepare the compound plate; thirdly, pressing a printing frame uniformly, pushing the printing frame upwards from the lower part of the provisional frame, adhering the printing frame to the polyester silk screen part of the provisional frame, and separating the provisional frame to obtain the product. Compared with the prior art, the method has the characteristics of not being limited by the type and the state of the internal stainless steel silk screen, manufacturing the final product with certain tensile force, preventing yield reduction caused by the breaking in the process steps and the like.