Deep Learning(DL) has achieved remarkable results in speech recognition and image object recognition, which has become the main processing method in these fields instead of traditional processing technology. DL is applied to radar target recognition and classification, and has achieved good results as well. Therefore, DL is tried to be applied in radar imaging. Based on the published literatures in recent years and the characteristics of radar imaging, the research progresses of DL in radar imaging are introduced. Its feasibility, sample selection, the generalization, and the evaluation of imaging quality are analyzed. The application prospects of DL in radar imaging are outlooked.