The invention discloses a high-stability coating material composition, a loading technique of active ingredient Pd and a preparation method of coating slurry. Besides a catalytic active ingredient (Pd), a rare earth catalyst promoter, an oxygen-storage material and activated aluminum oxide, the coating material composition is characterized by further comprising silicon carbide and tungsten oxide and taking a synergistic effect together with rare earth cerium oxide and lanthanum oxide; Pd is immobilized on a La modified coating material such as aluminum oxide and oxygen-storage material by virtue of an impregnating-precipitating method in advance; by replacing a conventional Ce/Zr oxide solid solution with a high-performance Ce/Zr/Pr oxide solid solution oxygen-storage material and by improving the preparation process and parameter of slurry, the slurry is remarkably improved in terms of properties such as fluidity, nano particle distribution uniformity and adhesion. After being aged at 1000 DEG C, the prepared catalyst for purification of motor vehicle tail gas still has excellent catalytic activity and high-temperature stability; in addition, the process is simple and the cost is low; therefore, the catalyst is applicable to industrial production.