In order to improve the positioning ability of ultra wideband network in non-cooperative indoor environment, the theory of centreless positioning algorithm was used to solve and analyze the output distance information of ultra-wideband ranging, and the relative positioning results were obtained. The positioning results of the system were compared with the results of the photoelectric calibration system, and the accuracy was evaluated. The results show that, compared with the traditional ultra-wideband positioning model, the combination of ultra-wideband ranging and centreless positioning algorithm can realize the centreless positioning and the relative positions among nodes, and finally determine the relative positions among nodes. The combination of UWB ranging and centreless positioning algorithm has good stability and accuracy in relative positioning, and can be widely used in various indoor and outdoor scenes.