Abstract: Due to the ion electric propulsion high specific impulse feature, the launch weight of the spacecraft will be greatly reduced under the same payload to implement the orbit maneuver of an asteroid exploration. The application of ion electric propulsion in deep space exploration is investigated in this paper. On the basis of the successful experience of foreign countries and the analysis of the requirements of the task, the scheme and application strategy of the ion electric propulsion system are designed, and its thrust,specific impulse, propellant weight and power are calculated for the main-belt asteroid exploring spacecraft to meet the present life level of ion thruster. The research results show that the developing ion thruster can meet the requirements of the main-belt asteroid exploration mission and have reference value for the design of the spacecraft.