Quantum technology have been exploited to increase the performance of classical devices in science and engineering fields, such as electronic information and computer technology. Radar, as a typical electronic information system, suffers more and more challenge in target detection, for the widespread applications of stealth and electronic countermeasure technology. The system models of target detection, and the related research advance of the combination of quantum technology and radar technique were overviewed. The basic concept, classification and typical instances of quantum radar system were introduced. The significant research progress of how quantum phenomena enhance the radar target detection performance was analyzed. Directions of future work including key technologies and main problems in the realization of quantum radar were presented.