The invention discloses a platinum rhodium thermocouple anti-carbon composite coating material and a preparation method thereof, and belongs to the technical field of inorganic functional coating materials. The platinum rhodium thermocouple anti-carbon composite coating material comprises a first coating material and a second coating material which are placed alternately, wherein the first coatingmaterial is a mixture obtained by adding Y2O3 ultrafine powder with the mass fraction being 20%-30% into Y2O3 sol gel, the second coating material is a mixture obtained by adding TaC ultrafine powderwith the mass fraction being 20%-30% into the Y2O3 sol gel, the diameter of the Y2O3 ultrafine powder is 40nm-60nm, the diameter of the TaC ultrafine powder is 40nm-60nm, and the thickness of the platinum rhodium thermocouple anti-carbon composite coating material is 30[mu]m-50[mu]m. The platinum rhodium thermocouple anti-carbon composite coating material prepared according to the invention is high in temperature response speed, good in adhesion and capable of being used for a long time in a reducing environment.