A catalyst for catalystic cracking is prepared from molecular sieve milk, aluminium sol, diasporite, clay and inorganic acid through mixing, and spray drying. Said process features its order of adding raw materials, that is, molecular sieve milk-aluminium sol-diasporite-inorganic acid other raw materials are not limited. Its advantages are high solid content of catalyst grout before spray drying,short colloid forming time, high productivity, and low cost and energy consumption.