Abstract: This paper studies the problems which detect targets in the background clutters of millimeter-wave high resolution radar,and proposes a nonparametric detection method,which not only does less computation,but also is able to detect multiple extended targets along distance corridor,based on the position(range)orrelation information of one-dimensional range images of high resolution radar targets.The experiments,based on real data of millimeter-wave stepped frequency high resolution radar,have certified that the method presented is a very effective detection strategy for muliple extended targets.