Abstract: Complex electromagnetic interference and strong ground clutter will seriously affect the detection of the target signal when airborne weather radar is used to detect the low-altitude wind-shear, resulting in the inaccurate estimation of wind speed. To solve these problems, this paper presents a method of wind speed estimation of low-altitude wind-shear in MMW (millimeter wave) frequency agile system. In this method, two dimensional pulse-to-pulse canceller (TDPC) prefilter is designed in each pulse group by using radar system prior information to prefilter radar echo and weaken clutter power. Then, the combined space-time main channel adaptive processing(CMCAP) is used to filter the echo data in two dimensional space-time,obtains the Doppler ambiguity estimation value of the wind-shear signal, finally transforms the estimation result in each pulse group from the Doppler frequency domain to the velocity domain, uses the dislocation difference table method to revise the speed ambiguity, thus obtains the real speed value of the wind field. The simulation results show the effectiveness of the proposed method.