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.