Abstract: It is very important to explore the ground clutter characteristics at a millimeter wave(MMW) band for improving both radar target detection performances and earth remote sensing.Aiming at the problem existing in the ground clutter measurement method of an MMW LFMCW radar scatterometer,this paper is focused on the system calibration,selection of effective independent sampling numbers,application of the software gate in data processing,and decrease in measurement errors.The measured results of the bush backscatter with a Ka-band LFMCW scatterometer are analyzed.The results show the bush clutter amplitude is subordinate to a Rayleigh distribution when the incident angle is less than 15°.