Abstract: In view of problem that positioning accuracy of existing underground positioning algorithm is difficult to meet actual demand, a three-dimensional positioning algorithm based on TDOA and AOA used in coal mine underground was proposed combining with special environmental conditions in coal mine underground. The positioning algorithm uses sensor base station to measure the time difference that radiation emitted by unknown node arrived to different base stations and relative angle between them, and realizes positioning through coordinate information of the unknown node and base station itself. The simulation results show that the algorithm based on TDOA and AOA can effectively eliminate the noise and random error of measurements, and improves positioning accuracy combining with positioning model.