Abstract: The present disclosure relates to a combined treatment method for surface modification of fumed silica, which comprises the following steps: (1) two sets of modification devices are used to jointly treat fumed silica; the fumed silica is modified with a modifier in the reaction furnace of each set of modification devices to obtain two groups of modified fumed silica and exhaust gas respectively; (2) the exhaust gas obtained in step (1) is separated respectively to obtain unreacted modifier and by-products, and the obtained by-products are input into the reaction furnace of the other set of modification devices as reaction assistants to participate in the modification reaction; and the obtained unreacted modifiers are returned to the reaction furnace of the original modification device for repeated use.