The invention is a catalytic cracking catalyst to reduce sulfur content of gasoline and its preparing method, synthesis gama-type molecular sieve by kaoline in-situ crystallization and making exchange sodium reduction or / and rare-earth ion exchange processing to prepare it, and its characteristic: the weight percent of sodium oxide contained in it is less than 0.75%, the ratio of zeolite to silica-alumina is above 4.5, and it adds one or several of the sourish metal elements: Cu, Zn, Fe, Al, Ni, Zr, Sn, Ga, Ti and V in weight percent of 0.1-10%. It has good zeolite dispersivity and excellent hydrothermal stability, good catalytic cracking property, and excellent function of reducing sulfur content of gasoline. It can be used by mixing with routine FCC catalyst and also be singly applied in the catalytic cracking process course.