Abstract: The influence of mixing FCC diesels with different distillation ranges on VGO hydrocracking performance was investigated. It was found that under the same reaction conditions, as the FCC diesel becomes heaver，the yield of light and heavy naphtha decreased, and the latent aromatic of heavy naphtha increased gradually；the yield of jet fuel was increased first and then decreased, while the smoking point of jet fuel decreased；the yield of ＞282℃ bottom oil was decreased and then increased with increase of BMCI value. The experiment results demonstrated that under the same reaction condition, as light FCC diesel blending ratio increases，the yields of jet fuel and heavy naphtha decreased, the latent aromatic of heavy naphtha increased, the BMCI value of ＞282℃ bottom oil gradually increased. When the mixing ratio of light FCC diesel was 30%，the BMCI value of ＞282℃ bottom oil was 13.31，which can be applied as a high-quality feedstock for SCR. Under the same conversion rate, with the increase of light FCC diesel ratio，the hydrogen consumption of hydrocracking reaction increases, the yields of light naphtha and heavy naphtha decreased. The yield of jet fuel, latent aromatics of heavy naphtha and BMCI value of bottom oil were increased, but the smoking point of jet fuel decreased.

Key words: FCC diesel, hydrocracking, jet fuel, tail oil