Abstract: The echo waves of radar received consist of direct wave and multipath wave which is reflected from earth (sea) surface and coherent with direct wave. For height finding of meter-wave radar with mutual coupling present at low-angle environment, a new improved weighted spatial smoothing technique is presented. First, through a special way to divide array making mutual coupling is none of the cost function of DOA (Direction-of-Arrival) estimation, this is equal to process DOA estimation without mutual coupling. Then obtained the optimum weight matrix using received data of array directly, not only auto-correlation matrix but also cross-correlation matrix of subarray are used to enhance the decorrelation performance of multipath coherent signals. New improved weighted spatial smoothing technique can improve the precision of DOA estimation for DOA estimation of meterwave radar with mutual coupling present at low-angle environment also. Theoretical analysis and simulation results demonstrate the merits of the new algorithm.