The present invention relates to a deep desulfurization method for a gasoline. According to the method, a gasoline raw material and hydrogen are mixed, and then enter a pre-hydrogenation reactor to carry out hydrogenation on diene in catalytic gasoline to obtain mono olefin; the pre-hydrogenation product enters a water washing tower to carry out water washing, partial alkaline nitrides in the gasoline is removed, the obtained material enters a catalytic distillation tower, partial thiophene sulfides in the gasoline is subjected to weight gain under an effect of an olefin thiophene alkylation catalyst on the upper portion of the catalytic distillation tower, and concurrently the gasoline is divided into three components such as light gasoline, heavy gasoline and light diesel oil; the heavy gasoline component enters a selective hydrodesulfurization reactor to carry out deep desulfurization, hydrogen sulfide generated during the reaction is removed from the desulfurization product, and the hydrogen sulfide-removed desulfurization product is mixed with the light gasoline to obtain the deep desulfurization gasoline product; and light diesel oil on the bottom of the tower is adopted as a hydrodesulfurization raw material, or is adopted as low freezing point diesel oil blending component to be subjected to blending producing. With the method, sulfur content in gasoline can be substantially reduced, and octane number loss caused by the deep desulfurization process can be reduced.