Micro-Doppler is one of the target physical characteristics. The radar signature of target with micro-motion can make fine characterization of the shape, structure and moving state of target, which reflects the nonstationary property of radar signal. Hence, it has great superiority in the analysis of sea clutter and target detection in case of high sea state based on micro-Doppler theory. In this paper, modeling of scattering clutter from time-varying sea surface and analysis methods of sea clutter Doppler are firstly reviewed based on the principle and characteristic of micro-Doppler, which shows the necessity of micro-Doppler. Then, applications and technological approaches of micro-Doppler in the sea surface target detection are introduced from the aspects of the micro-motion target modeling and detection methods of micro-motion signature. In the end, future research interests are pointed out according to the problems of present study.