A preparation method of a composite Raman photonic crystal microsphere belongs to the technical field of biomedical research, environment monitoring and clinic detection. The method includes the following steps: mixing an ethanol solution of zinc acetate, an ethanol solution of sodium hydroxide and a silica photonic crystal microsphere together, stirring the above mixture in a constant-temperature water bath for reaction, and obtaining a silica photonic crystal microsphere wrapped in zinc oxide nanoparticles; and mixing an ethanol solution of PVP and the silica photonic crystal microsphere wrapped in zinc oxide nanoparticles together, adding an AgNO3 aqueous solution and an NaBH4 aqueous solution, stirring the above mixture in a constant-temperature water bath for reaction, and preparing a composite Raman photonic crystal microsphere. The prepared three-dimensional ordered Ag/ZnO/SiO2 photonic crystal microsphere material is uniform and structured in shape. The preparation method is simple, is low in cost, high in sensitivity and high in stability, exhibits good repeatability, has a good surface enhancement effect, etc.