Abstract: In order to further study the displacement conduction effect about spatiotemporal evolution mechanism in overlying coal and rock during lower protective seam mining, the paper analyzed the changing process of coal and rock state, stress and permeability that were influenced by relatively backward displacement conduction and relatively weakened strength in the aspects of time and space, which based on theory of displacement conduction in overlying coal and rock. So, it confirmed the best regional hole arrangement and the best occasion for gas extraction in the protected coal seam. Combing with engineering practice at the same time, the response parameters for displacement conduction effect were used to investigate in the protected coal seam; the results showed that the gas pressure of protected coal seam changed in rising-stability-falling slowly-falling quickly-stability-rising-stability along the direction of lower protective seam mining, which was similar with shape of saddle. The gas flow and deformation rate of protected coal seam changed in stability-falling-rising slowly- rising quickly-stability-falling-stability along the direction of lower protective seam mining, which was similar with shape of "S". The lower protective seam mining was strong in stress relief and gas delivery in protected coal seam.