The invention relates to a preparation method of a heat-conducting friction braking material, and belongs to the technical field of preparation of friction braking materials. The preparation method comprises the following steps: freezing water-containing graphite by virtue of liquid nitrogen, carrying out ball milling to generate a monolithic layer from graphite, and modifying the graphite by virtue of gum and microorganisms, wherein the monolithic-layer graphite has excellent thermal conductivity and wear resistance, natural resin particles on the surface of the graphite modified by the gum and the microorganisms are increased, and the consistency of the graphite with resin is enhanced; calcining zinc oxide under an oxygen bearing condition, so as to obtain zinc oxide whiskers, wherein the zinc oxide whiskers have good wear resistance and slip resistance, and the material is unlikely to idle in use; and mixing the zinc oxide whiskers with substances such as modified graphite, the resin and the like so as to obtain a mixture, heating, putting the mixture into a mold, carrying out hot-press to obtain a blank, and finally sintering. The heat-conducting friction braking material prepared by virtue of the preparation method has a high heat conductivity coefficient, heat produced by the braking of a vehicle is easily diffused, and the material is unlikely to idle in the driving of the vehicle, so that the safety performance of the vehicle is improved.