This paper presents a novel wide beam UWB direction antenna for 1~2GHz distributional through-the-wall detection system. For the requirement of large coverage area, more than 140° aspect beam over the ultra wide band directional antenna is designed. The antenna consists of a basic reduced ground plane antenna and an additional reflection structure at one side of the patch. The reflection ground structure can adjust radiation patterns independent of properties of bandwidth. The measured E-plane beam width keep 140° and the H-plane beam width is less than 55° through the bandwidth (0.9GHz to 2.6GHz) which measured 10dB return loss. The maximum gain is more than 3dBi.