The invention relates to the technical field of copper-clad laminate production, in particular to a method for preparing a copper-clad laminate. The copper-clad laminate is prepared by using a double-sided glass cloth gum-dipped tablet as a surface material, and using a wood pulp paper gum-dipped tablet and a cellophane gum-dipped tablet which are mixed as an intermediate sandwich material as an inner material. Compared with a CEM-3 copper-clad laminate, the prepared copper-clad laminate has the advantages that a sandwich material part replaces part of the cellophane gum-dipped tablet with the wood pulp paper gum-dipped tablet, so the cost is reduced; the flexibility and mechanical processing performance of the copper-clad laminate are improved by adding the wood pulp paper gum-dipped tablet; the production efficiency and the heat resistance of the copper-clad laminate are improved compared with a CEM-1 copper-clad laminate.