Abstract: A quaternary ammonium salt was used to selectively extract vanadium from high concentration sodium molybdate solution. The effects of extractant composition, equalized pH value, contract time, reaction temperature, phase ratio on molybdenum and vanadium extraction were investigated. Selectively removed molybdenum from loaded organic phase was also studied. The results show that the extraction rate of vanadium can reach 99.60 % through five-stage countercurrent extraction with extractant composition of 15 % quaternary ammonium salt +12 % DL-2-octanol+73 % sulfonated kerosene, pH rate of 8.50, V_O/V_A ratio of 1: 2 at 25 ℃ for 5 minutes, while the molybdenum extraction rate is under 0.5 %, the separation coefficient of βV/Mo up to 63 000. The loaded organic is washed by 0.1 mol/L NaCl+0.3 mol/L NaHCO₃, on the condition of V_O/V_A ratio of 5: 1, contract time of 5 min, temperature of 25 ℃. Through five-stage countercurrent washing, 98.87 % of molybdenum and 0.4 % of vanadium are removed. Through stripping can achieve sodium vanadate solution, which contain 51.33 g/L of vanadium and molybdenum concentration is under 0.03 g/L. The study achieves separation of molybdenum and vanadium.