The invention discloses a sparse microwave imaging method, relating to the information acquisition and processing technology. By utilizing sparsity of microwave imaging observation, through introducing sparse signal processing theory into microwave imaging technology, after signal processing and information extraction, the geometrical and physical characteristics of an observation object such as space position, scattering characteristic and motion characteristic and the like are obtained, wherein the sparse signal processing theory is through searching sparse representation field of the observation object, obtaining sparse microwave signal of the observation object in space, time, frequency spectrum or polarizing field sparse sampling. According to the sparse microwave imaging method in the invention, the bottleneck problems existed in the prior art such as difficult system realization, complex imaging processing method, redundant information and difficult feature extraction and the like based on Nyquist sampling theorem and classic digital signal processing theory are solved, thus microwave imaging system structure and imaging complexity is reduced.