Abstract: The Pingshang Coal Mine is classified as a coal and gas outburst mine. To address the issues of prolonged coal sample exposure in conventional sampling methods and significant errors in gas loss estimation, a sealed in-situ sampling method for gas content measurement is proposed. An integrated sealed sampling device, combining motor-driven mechanisms, sampling, and desorption functions, was developed. The airtightness and feasibility of the device were verified through similarity simulation experiments, and field tests were conducted at the Pingshang Coal Mine. The results demonstrate that the measured underground gas desorption volume obtained via sealed sampling is 13.82%～16.18% higher than that of conventional methods, significantly improving the accuracy of gas content determination.