Abstract: Radar forward-looking high-resolution technology enables moving platforms to achieve fine angular resolution in the forward-looking area, offering significant application value and broad prospects in both military and civilian sectors, such as precision strikes, autonomous landing, and low-altitude penetration. By adopting the theory of spatiotemporal variability compatibility as a unified framework, this paper systematically elucidates the physical foundations and mathematical essence of radar forward-looking high-resolution imaging. It categorizes forward-looking high-resolution technologies into three main types: motion modulation, radiation modulation, and composite modulation, and deeply analyzes the implementation mechanisms and performance differences of various systems, including Doppler beam sharpening (DBS), bistatic forward-looking synthetic aperture radar (SAR), scanning beam sharpening (SBS), vortex electromagnetic radar (VER), and stochastic radiation radar (SRR), forming a complete forward-looking high-resolution technology system. Finally, the paper outlines future development directions for radar forward-looking high-resolution technology, aiming to provide a useful reference for researchers in the field.