Abstract: The electric propulsion has the characteristics of high specific impulse, long service life and highly autonomous cruise, which will significantly reduce the propellant mass and improve the load ratio when it's used for orbit maneuver operation during the cruise phase of asteroid detection. The electric propulsion system for asteroid detection is investigated. According to the mission requirements of the asteroid detection to the electric propulsion and the technical basis of the existing electric thruster, five kinds of electric propulsion system solutions are proposed and compared, the optimal solution is designed and the key technologies are analyzed.