The space-based passive radar provides a greatly improved capability for worldwide surveillance and anti-radiation missiles, compared with terrestrial and airborne based system. It is the purpose of this paper to discuss the system performance, technology characteristics of passive bistatic radar based on space-based illuminators. A preliminary guidance performance evaluation of this type of radar is conducted in this paper, which is shown that target detection can be achieved with reliable performance. In addition, a detailed analysis of the resolution characteristics and ambiguity function are discussed, which can provide detection accuracy on the mid-course guidance. And system analyses are performed to identify the best candidate configurations and to estimate the capabilities of this type of radar.