Measurement of atmospheric wind field is very important for national safety, weather forecasting, aerospace and military applications. At present, our country is lacking of the comprehensive measurement capability of large-scale wind field. Light detection and ranging (LiDAR) is the sole instrument to access the three-dimension wind field profiler directly. The proposed space-based coherent Doppler wind LiDAR accesses the target Doppler frequency shift and calculates its line-of-sight velocity using laser heterodyne technology. Comparing with the traditional LiDAR, it has the prominent features of high space-time resolution and high sensitivity in dimension, especially in weight and power consumption. Illustrations focus on its principle and key technology. The intending space-based feasibility and prospect of the proposed coherent wind LiDAR are also given.