The invention discloses an integral automobile exhaust purification catalyst and a preparation method thereof, and relates to preparation of aluminum oxide sol, modification of a plurality of oxides in the introduced La2O3, CeO2, BaO, SrO, CaO, ZrO2, CuO, SiO2 and the like, load of the modified aluminum oxide sol on cordierite honeycomb ceramic and loads of a plurality of catalyst active ingredients in La, Sr, Co, Cu, Mn, Fe, Pd and the like. The cordierite honeycomb ceramic is used as a carrier; the modified aluminum sol is loaded on the cordierite honeycomb ceramic carrier by adopting a vacuum impregnation method; and the catalyst active ingredients are loaded on a modified aluminum oxide coating by adopting the vacuum impregnation method. When the modified aluminum oxide coating with large specific surface area is used for loading a perovskite type rare-earth catalyst, the load is uniform, the bonding property is strong, the crystal form structure of the catalyst is not changed; and the catalyst has good catalytic activity, air-fuel ratio fluctuation resistance and sulfur dioxide poisoning resistance.