Aiming at the problem that the ultrawideband signal is easily interfered by the harsh downhole environment, which leads to the large error of the existing downhole personnel location method, an improved algorithm based on the combination of SDS-TWR optimization method and robust Kalman filter is proposed. In this method, two ranging values from the positioning tag to the adjacent base station can be measured in a positioning period, which are then used as two observation values of robust Kalman filter to improve the positioning accuracy and stability of the algorithm and suppress the random NLOS delay error of roadway. Simulation results show that under the same conditions, the proposed algorithm reduces the error by 35% compared with S-TDOA and 31% compared with asynchronous timing method, and the error fluctuation is small. Meanwhile, the NLOS delay error of roadway is suppressed, and the positioning accuracy of downhole personnel is effectively improved.