Abstract: Si-AlPO4-5/Al2O3 composite support was prepared by adding silica sol to AlPO4-5/Al2O3, and catalysts with different contents of SiO2 were prepared by impregnating the composite support with W-Ni active component. Samples of various composite support and catalyst were characterized by XRD and H2-TPR. The hydrodesulphurization (HDS) and aromatic saturation performance of the prepared catalysts were evaluated by a micro-reactor using dibenzothiophene and tetralin as model compound respectively. Test results showed that the structure stability of AlPO4-5 molecular sieve was good, it was not affected during the preparation. Catalyst prepared by Si-AlPO4-5/Al2O3 composite support having a SiO2 mass fraction of 12% exhibited the best HDS activity and tetralin conversion, which was in accordance with the TPR result.