Abstract: In order to explain phenomenon that roof leakage and rib fall of coal wall at 11050 end face in a mine，numerical modeling and site observation test are used to study the distribution characteristics laws of abutment pressure and the roof pressure behavior laws at fully mechanized face with large mining height in deep buried, thin bedrock, thick unconsolidated layers coal seam. The results shows that the scope of abutment pressure is gradually increased with the increasing of mining height, but the peak point is not increased. The periodic weighting length is shorter. The support load of middle workface and pressure coefficient of bottom workface is the biggest.