Hydrocarbon catalytic conversion method for producing propylene and light aromatic hydrocarbon

A method for producing propylene and light aromatic hydrocarbon comprises the steps of contacting heavy hydrocarbons and/or grease with a cracking catalyst containing modified beta zeolite in a first reactor for catalytic cracking reaction, contacting C4 hydrocarbon fraction and/or light gasoline fraction with the cracking catalyst containing modified beta zeolite in a second reactor for catalytic cracking reaction, and then leading the reaction products into a third reactor for reaction. The hydrocarbon-gasoline conversion method provided by the invention has the advantages of higher propylene yield and light aromatic hydrocarbon yield.