With the presentation of ″Internet+″ and continuous development of Internet of Things technology，the scenes to locate the staff and goods are increasing. At the same time，the demands of emerging fields（such as security monitoring，aero⁃space，unmanned industrialization operation，seas exploration，digital tourism）for indoor positioning are growing. To satisfy dif⁃ferent requirements，various positioning technologies were developed by the academia and industry，but they have great dif⁃ferences in the aspects of positioning applicability，positioning accuracy，etc. In comparison with other positioning methods，the UWB（ultra wideband）positioning technology has the unique advantages in positioning accuracy，real⁃time performance and data scalability. In this paper，the algorithm based on TDOA（time difference of arrival） was improved to reduce the difficulty of clock synchronization，and in combination with Kalman filtering，the error interference in transmission process was eliminated.The method can make the indoor positioning more accurately.