Abstract: Combined with the differential pressure gauge and the gas measuring instrument of comprehensive parameters, the portable detection device of underground gas extraction parameters can be used to test the flow rate, concentration, negative pressure and temperature of any single extraction hole or group holes. Besides, it can be adopted to check the accuracy of the gas measuring instrument of comprehensive parameters frequently applied in site. The device has some features, including high accuracy, simple structure, low cost, simple and convenient operation, etc. The problem is solved that the diversion pipes are not installed in single hole or part hole group of underground coal mine extraction holes, and the flow rate, concentration test cannot achieve, thus assures the comprehensiveness, accuracy and reliability of the gas extraction parameters test.