The characteristics of millimeter wave radar,including working frequency band,target detection and imaging ability,weather transmission characteristics,are numerically simulated and analyzed.Based on the analysis of the indicators and technical characteristics of typical millimeter wave (MMW) radars in western countries,the development trend of MMW radars is given.In view of China’s space target detection requirements,overall problem of long-range MMW radar technologies are studied.The key technologies that restrict the design of radar system are analyzed,and the technical solutions are proposed.