Abstract: The environment of the fully mechanized working face in coal mines is harsh and the dust concentration is high.When ultra wide band(UWB)is used for positioning, it is easy to be interfered by dust.UWB ranging will have certain errors, so the positioning precision cannot meet the requirements of intelligent coal mines.To order to solve this problem, the principle of UWB ranging is analyzed, and it is pointed out that the main factors affecting the precision of UWB ranging are multipath effect and non-line-of-sight propagation.The generation of multipath effect and non-line-of-sight propagation is closely related to dust concentration, and the influence of dust concentration on the precision of UWB ranging in coal mines is explored through experiments.The experimental results show that the UWB ranging error increases as the dust concentration increases, and the growth rate of UWB ranging error accelerates.