Abstract: In view of problems of difficult deployment and high cost caused by a lot of wired communication cable and low intelligence of request for help in emergency existed in current accurate personnel positioning system of coal mine underground, an intelligent accurate personnel positioning system for mine was designed. In the system, personnel label position is acquired exactly by use of time of arrival ranging method based on ultra wide band positioning technology, personnel label information collected by card reader is uploaded to substation through data concentrator by use of LoRa wireless communication technology, and information of request for help is sent to manager automatically through emergency processing plan when persons lose ability of triggering help button manually. The test results show that the system can achieve reliable wireless data transmission with bit error rate of less than 5% within 2 km, whose positioning accuracy is 1 m, and automatic alarm rate is above 93.5% when persons lose ability of triggering help button manually.