Abstract: With the technology development of deep space exploration, near-earth asteroid exploration has been scheduled, and subsequent deep space exploration is also under planning. By analyzing deep space exploration demand of foreign countries for ion propulsion and its application, this paper depicts with emphases the research and development of ion thruster which will meet the requirement of Chinese first near-earth asteroid exploration mission. Based on the mature technology of current ion thruster, the study aims to enhance its performance so which can work in dual modes with thrust level at 40 mN and 60 mN respectively. With different combination, it can achieve five thrust levels as 40 mN、60 mN、80 mN、100 mN and 120 mN to meet the requirements of asteroid exploration missions.