Abstract: For the problem of time degradation of safety performance of lithium battery, power supply management data and operation information of backup power supply of coal mine monitoring and communication system and auxiliary transportation equipment are collected and analyzed, capacity attenuation analysis, EIS impedance spectrum analysis, thermal runaway expansion and safety test, extrusion test analysis and power management system accuracy test were carried out for large-capacity lithium batteries in use. The test results show that the performance of lithium battery and the test precision of battery management system are attenuated, and the safety of lithium battery is decreased. Based on the field data analysis and test results, the countermeasures for safety management of large capacity lithium battery in underground coal mine are proposed.