Aiming at the difficulty of synchronizing the clock of TDOA in the ultra-wideband indoor robot positioning system and the various interference problems in measurement, a new method for indoor robot TDOA asynchronous non-reference node ranging is proposed. This method uses the time calculated from the actual measurement as a correction factor to construct a ranging algorithm model for the master base station without a reference node under an asynchronous clock. The measurement information of the master and slave base stations can directly calculate the robot's arrival distance difference; propose an association weight The new algorithm of value filtering combines the moving average to obtain the arrival distance difference state matrix, which effectively reduces signal interference. And from the measurement performance, ranging and positioning and other aspects of error analysis. Experimental results show that 98% of the ranging accuracy is maintained within 10cm, and measurement deviation will not occur with long-term operation, and it has good positioning accuracy, which can meet the positioning needs of indoor robots.