Abstract: The 80509 isolated island caving face is surrounded by gobs. The air leakage law of "islands" workface is very complicated and variable .According to the research, it got conclusion that isolated island caving face has much more air leakage than normal mining method and the tail position of the workface which has more possibility to generate spontaneous combustion is the center of leakage from gobs. Due to pressure and gas releasing in advance during the mining of the adjacent workface, isolated face has a relatively low gas emission. Under the circumstance of insuring the gas concentration in workface not over-limited, it need to decrease the negative pressure of high drainage roadway. Under the circumstance of insuring the gas concentration in workface return air and methane special lane not over-limited, the high drainage roadway should be closed. As the isolated face is surrounded by gobs, there are some places are easier to generating spontaneous combustion such as open-off cut, stopping position and adjacent gobs.