Abstract: A gas abnormity alarm method was proposed which used monitoring data of safety monitoring system, and new distribution ideas of methane sensor and air direction sensor for gas abnormity alarm were proposed. When monitoring value of the methane sensors suddenly changes which are distributed in working face, upper corner or back airflow, corresponding judgment logic relations are set for judging gas abnormity and alarming according to installation position of the sensors. When reverse airflow appears in air direction sensor in intake air roadway, the judgment logic relations are taken for judging gas abnormity and alarming. The application shows that the method can judge gas abnormity quickly.