Nowadays, The USA, Europe and Japan have established a series of plans of deep space exploration [1]. Our country also has lunar exploration program and Mars exploration planning. With growing fierce competition for outer space, strategic resource exploitation is getting more attention. The space-borne subsurface sounding radar is a natural payload for deep space exploration on orbiter mission. Goal of this radar is to investigate surface and subsurface of planet/asteroid and provide radar data that supply information concerning dielectric interfaces [2][3]. This paper firstly focuses on two key technologies of the radar: ground penetrating imaging technology and clutter mitigation technology, some effort of simulation is made to deep understanding these two technologies. Our team is also lucky to get some outlay support to design an experimental prototype. The system and its latest field experiment result are briefly introduced at the end of the paper.