The catalytic activity of ultrastable Y zeolite (USY) for m-xylene isomerization in the presence of hydrogen is markedly promoted by physically mixing with Ni(S)/Al2O3 under the conditions of 603 K and 1.0 MPa. The study on H-D exchange of the OH groups on the USY zeolite surface showed that the exchange rate in Ni(S)/Al2O3-USY was five times higher than that of USY alone. It was considered that active hydrogen species, formed on Ni(S) sites and spilled over to Al2O3 and then to USY, promote the acid catalysis on the USY.