Abstract: In order to improve the positioning accuracy of railway trains and personnel, aiming at the positioning requirements of intelligent railways in high-speed and low-speed scenarios, and combining with the positioning technology of the 5G NR, this paper proposed the uplink and downlink positioning solutions based on 5G NR. Based on the positioning technology principle of time difference of arrival, the paper selected the downlink arrival time difference positioning method (DL-TDOA) and uplink arrival time difference positioning method (UL-TDOA) to design the uplink and downlink positioning reference signal, time measurement feedback and positioning process, ensured that the intelligent railway meets the meter level positioning accuracy defined in the technical report of the third generation partnership project (3GPP TR) under the low-speed scenario, and proposed the potential positioning enhancement technology under the high-speed scenario and the tunnel scenario. It can provide technical reference for the multi scene positioning of the intelligent railway.