Abstract: Based on theory analysis and field test, change laws of O₂ and CO concentrations with the distance are obtained in 3206 and adjacent goafs. On the basis of analyzing datum, two oxidation zones which are located in the crossheading of return air adjacent goafs are presented. Rock bulking coefficient of 3206 and adjacent goafs is analyzed and air leakage boundary is obtained by combining ventilation system pressure. Finally, using the superposition of air leakage boundary, residual coal distribution and gas change, spontaneous combustion danger zone of 3206 insular face is divided into dynamic and static danger zones. The results show that dynamic danger zone of return air adjacent goafs is the emphasis of fire prevention and extinguishment in 3206 face.