Abstract: By establishing the mathematical model about the rock burst type of coal wall overall being pushed out in "three hard" coal roadway of Datong Coal Mining Area,the writer studied the mechanism of this type.Under the condition of having separated the seam and roof,the occurrence of coal as a whole to be moved and of having the vertical stress is very small,because it′s possible to happen that the coal is vulnerably squeezed out and moved outward as a whole.