Abstract: According to the geological structure and mining elevation of Hongsong coal mine,determining range was delimited in M₁₇ coal seam.The paper introduced the selection about pressure measuring ways and pressure measuring sites,and analysed the factors that affect the gas pressure;detected the gas pressure in M₁₇ coal seam accutately and efficiently in the determining range;provided important parameters for the identification of coal and gas outburst in Hongsong mine.