Abstract: Multiple-Input Multiple-Output (MIMO) radar is a novel radar system that sends particular waveform by multiple transmitting antennas and receives the scattering signal by multiple receiving antennas, before signal fusion processing. In this paper, the development of MIMO technology is reviewed. Two kinds of MIMO radars are introduced in particular, besides, both the theoretical and experimental progress of MIMO are summarized subsequently, the future development is discussed as well as finally.