Abstract: Stepped frequency radar has ability of high range resolution and its applicability has been well documented Relation between intermediate frequency bandwidth and range window of HPRF stepped frequency radar is analyzed in this paper The method using multiple receiver channels can cover the entire interested range, but it complexes system This paper proposed a digital multichannel receiver which aimed to enlarge the search coverage of stepped frequency radar without increasing system equipments Then, we analyzed the drawback of conventional digital multichannel receiver and proposed an efficient structure based on polyphase filter Finally, computer simulation demonstrates the effectiveness and feasibility of the proposed method