Abstract: At present, the risk assessment of coal and gas outburst is not yet to formulate relevant industry standards. In order to make the evaluation work more scientific and more standardized and more practical, based on the previous assessment, we analyze and modify the reliability of gas content which combines with the pause time and drilling depth and coal ash and gas composition and gas occurrence law of the exploration of gas drilling according to the complete degree of field investigation and data collection. The gas pressure is obtained according to the gas content of the Langmuir relation. Other gas parameters use the measured data first. And if there is no measured data, the gas parameters refer to the same coal seam of adjacent mines or adjacent coal seam gas parameters according to the principle of proximity spacing.