The Jiangjunshan-Baishui fault is a branch of the eastern section of the northern margin fault of the Weihe Basin. It is located in front of Jiangjun Mountain and East Taibai Mountain and extends northeast to Baishui County. The existing data and research results suggest that the Jiangjunshan-Baishui fault is an active fault in the Late Pleistocene. In this paper, the distribution and activity of the fault were studied based on some methods such as geomorphological and geological surveys, shallow seismic exploration, composite drilling section exploration, and Quaternary sediment dating. The results show that the Jiangjunshan-Baishui fault, with an overall trend of NE dipping S,is a piedmont buried fault. The latest active age of the fault is the late Middle Pleistocene. No evidence of activity has been found since the Late Pleistocene. It is therefore concluded that the Jiangjunshan-Baishui fault is an active fault in the Middle Pleistocene.