The interaction of vanadium and nickel in USY zeolite has been investigated by X-ray diffraction, nitrogen sorption, Fourier-transform infrared spectroscopy, temperature-programmed reduction, and n-hexane cracking reaction. There is an interaction existing, either direct or indirect through nonframework aluminum, between vanadium and nickel. This leads to the inhibition effect for vanadium and nickel to affect the catalytic and physical-chemical properties of USY zeolite. Nickel can inhibit the destruction of USY zeolite caused by vanadium. Vanadium can suppress the coke formation due to the presence of nickel.