Abstract: Aiming at the problem of gas concentration overrun at upper corner and ventilation roadway of 1202 isolated working face during the process of mining, we adopt some research ways like numerical simulation and engineering practice. In the 3D-goaf physical model, we first time add two isolated working faces in it and simulate gas control effect by high-low position united draining technology. We analyze and compare measured value and simulation result of gas concentration: the average gas concentration measured value of transportation roadway high position fissure hole is 9.87%, and the simulation value is about 10%. The average gas concentration measured value of transportation roadway and material roadway low position fissure hole is 3.01% and 2.91% separately, and the simulation value is about from 3% to 5%; the average gas concentration measured value of upper corner and ventilation roadway is 0.28% and 0.19% separately, and the simulation value is 0.32% and 0.25% separately. The numerical simulation value is consistent with the engineering practice measured value, and the result shows the scientificity and rationality of extraction scheme by simulation way.