Abstract: The conversion mechanism and path of the type sulfur in raw oil, such as thiophene, benzothiophene, and sulfide ether in the process of catalytic cracking, and the results of calibration of the type sulfur in catalytic gasoline were compared with the influence of the catalytic operation conditions, catalyst type and raw oil composition on the cracking and desulfurization process of the type sulfur. The adsorption desulfurization and hydrofining of two main desulfurization technologies were discussed. The beta carbon positive ions were easily formed in the center of the catalyst B acid and further converted into different intermediate products, then through the hydrogen transfer reaction and the cracking reaction cracking desulfurization of hydrogen into the gas phase or the generation of alkyl pyridine and other sulphides mainly into the gasoline distillation segment, benzothiophene and dibenzothiophene are more difficult than thiophene to crack the ring. Its desulfurization products mainly enter the diesel distillation segment. Lower reaction temperature, higher agent oil ratio, longer reaction time, high acid density catalysts with high cell parameters, and more hydrogen supply are beneficial to the removal of type sulfur.