Generally, reverse fault would create some fault caves during its active stage, by these caves (channel-ways) gas migrated through the strata quickly, and gas migrated through the caves by the form of surge flow. In case of the caves reaching to the grownd surface, much gas would emit through the caves, and only a little gas inject the neighboring reservoirs in both sides of the fault. The gas which could inject neighboring reservoirs possessed a clear selectivity. First of all, the gas injected reservoir with good permeability, sharp dip-angle and more shallow burial. Without other power except buoyancy, only little gas could inject reservoir in the lower block of fault. When fault was in a static stage, fault caves would be disappeared, the channel-ways which gas migrated through strata were rock pores in crushed zone, and the rule of gas migration followed the Darcys Law. Migration velocity of gas in fault zone increased, exponentially, with grain size of filling matter becoming coarser and fault dip angle becoming larger, and the velocity decreased, exponentially, with the argillaceous content increased in fault filling.