According to the characteristics of the beam scanning and beam distribution in space of 3-D radar, a plots centriod algorithm of the peak-searching in range and the centriod at azimuth and pitch is designed and applied for radar. The result has shown that the use of algorithm not only reduces the probability that weak targets is filtered out, but decreases the split of the plots in range and at azimuth and pitch so as to provide a reliable basis for further track processing. The algorithm is easily implemented in engineering application because it is a recursive algorithm and takes less memory.