The invention relates to a composite material, a high frequency circuit board prepared from same and a preparation method thereof. The composite material comprises the following components: 20-70 parts of thermosetting mixture containing a hydrocarbon resin with the molecular weight of less than 11000 and more than 60% of ethylene group and a solid styryl resin with unsaturated double bond and medium or low molecular weight; glass fiber cloth; filler powder; and fire retardant and curing initiator. The prepared high frequency circuit board comprises a plurality of prepreg layers which are superimposed and prepared from the composite material, and copper coils which are pressed and coated on both sides of prepreg layers. The preparation of the prepregs prepared by the composite material ofthe invention is simple and the high frequency circuit board prepared from the prepregs has low dielectric constant and dielectric loss angle tangent, good heat resistance and convenient technological operation so that the composite material of the invention is suitable to prepare circuit boards of high frequency electronic equipments.