Abstract: For the problems that coal seam gas pressure is difficult to accurately determine due to bed separated fissures development in large rock-gateway, high strength of artificial record, based on the analysis of existing measurement techniques, we propose "two sealing and one grouting" capsule sealing technology and develop the device. In this technology, the grouting pressure is 4 MPa and sealing time is not more than 30 min, combined with CPD8M coal seam gas pressure automatic monitoring meter can determine the coal seam gas pressure accurately and automatically. Applications have shown that this method has the advantages of simple operation, effectively plugging surrounding rock crack under large section of multiple injury and can achieve accurate automatic measurement of gas pressure in coal seam.