The invention relates to a preparation method of a CEM-1 copper-clad plate and belongs to the technical field of copper-clad plates. The preparation method provided by the invention has the benefits that through adding aluminum oxide, aluminum nitride, boron nitride, silicon nitride, silicon carbide and the like in the processing process of electronic-grade glass fiber cloth and bleached wood pulp paper, the heat conductivity coefficient is high, and the defect of low heat conductivity coefficient of existing CEM-1 copper clad plate paper serving as an inner-layer reinforcing material is overcome; in a resin formula, epoxy resin with low bromine content or no bromine is used as main resin, a filler capable of improving a plate CT1 is added, and a certain weight of fillers with excellent thermal conductivity and other functional fillers are added to improve the various comprehensive properties of the plate.