Abstract: In this article, the immobilized 1-heptyl-3-methylimidazolium borofluoride ionic liquid was synthesized by two-steps synthesis. The ionic liquid was applied as extracting reagent for oil desulfurization using hydrogen peroxide (30%) as the oxidant. The desulfurization conditions were checked and optimized by changing the ratio of ILs/oil, extraction time, temperature, and rate. Theoretical stages of the multi-stage countercurrent extraction desulfurization of the ionic liquid were also calculated and verified by three sets of parallel string class simulation experiment under the optimized conditions. The results show that the best desulfurization rate of 77% for FCC gasoline was obtained after 60 minutes at V(IL):V(H2O2):V(Oil)=1:1:10, 60℃ and revolution speed of 600 r/min. After the 4 stages counter current extraction, the sulfur content of the feed gasoline decreases to 10 μg/g with the sulfur removal efficiency of 94% and the gasoline recovery of 95%, which shows good perspective for industrial applications.