Due to the substantial development of DC transmission technology, DC pipeline transmission is an integrated and underground medium which can solve the power transmission requirements of special occasions. In the real GIL system, epoxy resin composites are usually used to cast insulators. Under DC voltage, surface charge accumulation on the insulator will cause serious local electric field distortion, which may in turn cause partial discharge, even resulting in surface flashover. Surface fluorination is one of the important means for regulating surface molecular of polymer insulations, providing feasible ideas for insulator surface modification due to its advantages such as simple process, mature technique, and cheap cost. Therefore, based on the researches at home and abroad, this paper analyzes the mechanism of surface fluorination modification in three aspects including dielectric parameter regulation, surface charge restriction and flashover voltage promotion. It is indicated that fluorination treatment can help to significantly change the physiochemical characteristics and the dielectric parameters of epoxy resin, besides, the electrical performance of the epoxy resin composite has been obviously improved. Meanwhile, it proposes existing problems in the current research and application prospects of surface fluorination technology.