Abstract: Wide-band digital array radar (WB-DAR) has not only good performance in anti-interference and multifunction but also the advantage of high range resolution and the ability of target classification and recognition. On the other hand, the large bandwidth signal imposes the constraints of aperture transit time, therefore WB-DAR needs variable fractional delay (VFD) filter to obtain digital delay compensation instead of phase shifter in traditional narrowband phased array for accomplishing beamforming. Based on the typical structure of one receiving channel in WB-DAR, which consists of multiple stage anti-aliasing filters and a variable fractional delay (VFD) filter, a new optimal design method is proposed. Compared with the traditional method, the proposed method can apparently reduce the filter order of receiving channel and maintain the same performance.