The TiO ₂-SiO ₂-Al ₂O ₃ composite support was prepared by sol-gel method, and then the MoP/TiO ₂-SiO ₂-Al ₂O ₃ catalyst was prepared in the way of co-impregnation. XRD results show that the diffraction peaks of TiO ₂ crystalline phase is due to anatase and SiO ₂ is mostly amorphous dispersed in γ-Al ₂O ₃ cystal surface. After in-situ reduction, the hydrodearomatization (HDA) activity of the catalyst was investigated in the fixed bed reactor. The results suggest that the mole ratio of Ti, Si and Al have a great influence on the activity of composite support catalyst. HDA activity of the MoP/TiO ₂-SiO ₂-Al ₂O ₃ catalyst shows the highest activity (65.6%) when the ratio of n(Ti)∶n(Si)∶n(Al) was 1∶1∶4, the Mo loading amount is 20%. In addition, the results also show that the HDA rate of the catalyst with the composite TiO ₂-SiO ₂-Al ₂O ₃ support was 19.6% and 13.6% higher than the traditional cataslysts of γ-Al ₂O ₃ and SiO ₂-Al ₂O ₃, respectively.