To solve the problem that the forward direction of radar does not have enough Doppler bandwidth thus it is difficult to use the Synthetic Aperture Radar (SAR) imaging technologydeep researches have been carried out on the radar forward imaging technology from multiple aspectsand have been applied in missile precision striketerrain recognitiontarget positioning and aircraft autonomous landing.This paper comprehensively introduces the history of the researches on forward-looking imaging technologyand make classification to the technology systematically according to imaging principleradar model and detection signals.The basic principles and characteristics of the imaging technology based on convolution inversion single pulse imaging technologymicrowave correlation technologyarray radar imaging and bistatic forward-looking imaging are mainly described.The research status and development trend of various forward-looking imaging technologies are summarized.