The invention discloses a system and method for treating a high-concentration salt radioactive waste liquid through an electrically-driven membrane. The system comprises a concentrated water tank, a fresh water tank and an electrically-driven membrane device. The concentrated water tank is connected to the electrically-driven membrane device through a concentrated water pipe so that concentrated water circulation is formed. The fresh water tank is connected to the electrically-driven membrane device through a fresh water pipe so that fresh water circulation is formed. The concentrated water tank is connected to the electrically-driven membrane device through a polar water pipe so that polar water circulation is formed. The method comprises the following steps: respectively pumping the waste liquid into the concentrated water tank and the fresh water tank to enable the waste liquid in the fresh water tank to form fresh water circulation between the fresh water tank and a fresh water chamber and to enable the waste liquid in the concentrated water tank to respectively form concentrated water circulation and polar water circulation between the concentrated water tank and a concentrated water chamber and between the concentrated water tank and a polar water chamber, so that the electrically-driven membrane device starts working until the waste liquid is treated to a target level. Through the system and method, the polar water pollution can be effectively avoided so that the generation of the secondary radioactive waste liquid can be avoided.