Abstract: In order to explore the impact of drainage quantity of advanced diversion hole on distribution of oxygen and methane in gob,using ANSYS numerical simulation software,the establishment of complex goaf three-dimensional mathematical model is established and the numerical simulation is carried out. Results demonstrates that the reasonable range of the quantity of drainage in advanced diversion hole is from 57 m³/min to 68 m³/min, and CO concentration at upper corner is less than 12×10^-6;the maximum gas concentration at 81004 working face,upper corner,and return air lane is controlled within 0.8%,which can ensure the safety of working face.