With the rapid development of oil refining industry, the annual generation of global spent hydroprocessing catalysts is gradually increasing. Spent hydroprocessing catalysts are rich in organic pollutants and metals including molybdenum, vanadium, nickel, and aluminum, which will lead to not only serious deterioration of ecological environment but also waste a great amount of resource. In this study, a process featured by air roasting-alkaline leaching was proposed to treat the spent hydroprocessing catalyst in the purpose of recovering molybdenum and vanadium. Thermogravimetric (TG), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) techniques were employed to characterize the raw spent catalysts, the roasted product and the leaching residues. Air-roasting can make the metal sulfides convert to oxides which were able to be dissolved into leaching solution by sodium carbonate. Thermodynamic analysis showed that the low-temperature leaching can separate molybdenum and vanadium from aluminum and nickel in the spent catalysts. The effects of air roasting temperature, sodium carbonate concentration, reaction time, leaching temperature and liquid to solid ratio on the leaching rate of molybdenum and vanadium were investigated by the single factor experiments. The experimental results showed that the leaching rates of molybdenum and vanadium reached 98.02% and 94.36%, respectively, under the optimum conditions with roasting temperature of 500℃, sodium carbonate concentration of 4 mol/L, leaching temperature of 80℃, reaction time of 90 min and liquid-solid ratio of 20:1. In order to maximize the recovery of molybdenum and vanadium, the two-stage counter current leaching process was adopted subsequently, and the leaching rate of molybdenum and vanadium were able to maintain at 98% and 97%, respectively. The leaching residue mainly contained Al2O3, NiO and NiAl26O40, and most of molybdenum and vanadium transferred into leaching solution. The advantage of this process is that molybdenum and vanadium can be fully recovered and satisfactorily separated from nickel and aluminum with the mild leaching conditions, which is benefit for the following treatment of leaching residues.