The present invention relates to a composite material, a high-frequency circuit substrate made therefrom and a making method thereof. The composite material comprises: thermosetting mixture including more than one liquid vinyl resin with the molecular weight being less than 10000 containing polar functional groups, and a polyphenylene ether resin with the molecular weight being less than 5000 containing unsaturated double bonds at the molecule terminal; fiberglass cloth; powder filler; flame retardant and cure initiator. The high-frequency circuit substrate made from the composite material comprises a plurality of prepregs mutually overlapped, and copper foils respectively covered on both sides of overlapped prepregs; each prepreg is made from the composite material. The composite material of the prevent invention realizes easy manufacturing of the prepregs and high bonding force to the copper foil. The high-frequency circuit substrate made from the composite material has low dielectric constant, low dielectric loss tangent, and excellent heat resistance, and is convenient for process operation. Therefore, the composite material of the present invention is suitable for making the circuit substrate of a high-frequency electronic equipment.