Ultra wide band (UWB) has emerged as a promising fuction in the field of indoor positioning. The geometric position relationship between UWB base station and the measured target affects positioning accuracy directly. Based on the basic principles of UWB positioning system, this paper takes the horizontal dilution of precision (HDOP) as the evaluation index of positioning accuracy, and proposes the layout optimization method of UWB base station under both ideal condition and actual conditions through simulation and practical experiment verification. The three-stage design method for layout optimization of UWB base station in underground parking lots is developed, which provides a scientific workflow for the practical application.