Sparse microwave imaging radar is a newly developed concept of microwave imaging system,which tries to combine the traditional radar imaging system with sparse signal processing theories,achieving the aim of reducing the complexity of microwave imaging systems and enhancing the system performance.In this paper,we introduce some basic concepts of sparse signal processing theory,and then apply it to the traditional radar imaging system to get the mathematical model of sparse microwave imaging system.We analyze the factors that determine the performance of sparse microwave imaging radar,including scene,waveform and platform.According to the radar model,we analyze how these factors influence the radar system and how to optimize them.Simulation results of the sparse microwave imaging radar system are also provided. Sparse microwave imaging radar is a newly developed concept of microwave imaging system, which tries to combine the traditional radar imaging system with sparse signal processing theories, achieving the aim of reducing the complexity of microwave imaging systems and enhancing the system performance. In this paper, we introduce some basic concepts of sparse signal processing theory, and then apply it to the traditional radar imaging system to get the mathematical model of sparse microwave imaging system. We analyze the factors that determine the performance of sparse microwave imaging radar, including scene, waveform we analyze how these factors influence the radar system and how to optimize them. Simulation results of the sparse microwave imaging radar system are also provided.