Abstract: In order to prevent coal spontaneous combustion in high gas mine and spontaneous combustion seam during gas drainage process, by regularly checking the gas of drainage drill, we find the laws of CO. Based on the distribution of high concentration CO drillings and near gob fire zone position, we use measures of measuring air leakage by tracer gas and monitoring CO gas change in adjacent goaf by construction drillings to verify CO source and judge goaf spontaneous combustion state.We use SF6 to find the air-leakage passage, and construct drill hole to detect CO concentration of near gob to judge the state of spontaneous combustion in Goaf.