Abstract: Oxidative desulfurization of thiophene by phase transfer catalysis has been investigated with hydrogen peroxideformic acid as the oxidant, thiophene in nheptane as model compound of light oil. It was shown that the desulfurization rate of thiophene was 86.36%, under the conditions of water/oil ratio being 1∶1, after1.5h at temperature of 45℃ by TBAB. From the kinetics investigation, it was shown that when the model compound was oxidized by hydrogen peroxideformic acid with TBAB as phase transfer catalyst, the reaction was pseudo firstorder reaction with rate constants of K30℃=0.6152h-1, K40℃=1.2672h-1, and K50℃=0.8581h-1. The essential process of catalytic oxidation is the transfer of oxidizing active ingredients RCOOO- from water phase to oil phase by Q+, and the cycling models of oxidative desulfurization of thiophene by phase transfer catalysis(Q+X-) is builted.