Abstract: The various high-power electric propulsions based on the space nuclear power were compared and chosen in this paper. The high-power Hall electric propulsion was confirmed as the top choice because of simple structure, high thrust power ratio, high reliability, and so on. Then the 1 MW high-power Hall electric propulsion system was designed with the background of the large-scale Mars exploration, which consists of five 200 kW Hall-thrusters. The propulsion system will be used to complete the orbital transfer from low earth orbit (LEO) to Mars orbit and the exhausted propellant mass is 3.89 t less than that exhausted by the chemical propulsion.