The invention relates to a method for low temperature preparation of a diboride-carbide solid solution multiphase ceramic by a reaction hot press sintering method, and belongs to the technical field of multiphase ceramic materials. The problem of high sintering temperature of an existing diboride-carbide multiphase ceramic is solved. According to the method for the low temperature preparation of the diboride-carbide solid solution multiphase ceramic by the reaction hot press sintering method, transition metal diboride and carbide which can produce solid phase exchange are selected, a compositepowder body is prepared by a high energy ball milling process, under the protection of vacuum or inert atmosphere, and the reaction hot press sintering is carried out to prepare the dense diboride-carbide solid solution multiphase ceramic. The solid-phase reaction and solid solution coupled synergistic process in the sintering process is fully used, compared with traditional hotpress sintering process for the preparation of multiphase ceramic materials directly using target diboronized and carbide powder bodies, the sintering temperature of the materials can be reduced by 250 DEG C to 400 DEGC, it is ensured that the material grain size is uniform and small by low temperature sintering, and the strength and toughness of the multiphase ceramic obtained are significantly improved.