In view of problem that coal mine safety monitoring and control system would take place false alarm in practical use because of external interference, the paper analyzed causes of happening false alarm in coal mine safety monitoring and control system, puts forward a processing method of false alarm by PC software. The method can judge false alarm of transmission line interference, unstable sensor, unstable power supply by change status and duration of monitoring data of monitoring system, so as to avoid occurrence of false alarm, improve stability and accuracy of coal mine safety monitoring and control system.