When radar operates on the sea in a looking-down mode, the strong sea clutter affects the target estimation and analysis seriously.The characteristics of sea clutter for different emplyments of radar may be very different.Therefore,only by analyzing and understanding the influence characteristics of sea clutter for radar,can we design an appropriate single processing method and predict the detection performance.Based on the field experimental date of radar,a suitable sea clutter backscatter coefficient model and a real-time sea clutter echo signal power computation method are proposed.Finally,the effectiveness and feasibility of the method are proved by comparing the theoretical sea clutter calculation results with the measured sea clutter results of radar.