Abstract: Abnormal gas distribution area at 5304 fully mechanized working face in Tangkou Coal Mine seriously affects production safety. Gob gas distribution range was calculated according to gas fractured zone height and gob fissure O-ring distribution theory. With FLUENT, gob gas distribution of 5304 woking face was simulated. The results show that the gob gas can be divided into three plane feature regions, fractured region I, compaction region II, upper corner gas accumulation area III; the height of gas fractured zone is 36 m. With the increase of height, the methane concentration in the gob increased gradually; high level drainage borehole should be set higher than the half height (17.5 m) of the gas fractured zone.