Abstract: Sulfur compounds in VGO of SCO（Synthetic Crude Oil） from Canadian oil sand bitumen were identified with GCPFPD and GCMS methods. The sulfur compounds in VGO of SCO are mainly C3~7dibenzothiophene, while those in FCC liquid products are short chain dibenzothiophene and a few alkylated benzothiophene and alkylated thiophene, and the percentages of these three sulfur compounds are 82.04%, 13.42% and 0.56%, respectively, and they are difficult to be removed by hydrogenation. The mixtures of VGO which mixed with SCO and Dagang in different proportion were processed in FCC reactor. With the increase of proportion of mixtures, the sulfur content of alkylated benzothiophene and alkylated thiophene in FCC liquid products reduce gradually, and the dominant part is short chain dibenzothiophene, especially 4-MDBT indicating the characters of hydrogenation of SCO. The content of sulfur in liquid products and diesel distillate increases, while it is reduced in gasoline distillate.