An FCC gasoline oxidizing desulfurization method with a composite acidic ionic liquid includes the steps of mixing the composite ionic liquid, an oxidizing agent and FCC gasoline, performing desulfurization at 25-80 DEG C under normal pressure for 0.5-1.5 h, and cooling the reaction product to room temperature, allowing the reaction product to stand for layering the reaction product, wherein an upper layer is a desulfurized oil product. The composite ionic liquid is composed of pyridine p-toluene sulfonate ionic liquid and alkyl pyridine tetrafluoroborate ionic liquid according to the molar ratio of 1-4:20.