Abstract: Taking the geological unit investigation report for background,Application of computer in a coal seam mining under thick magmatic rocks when the law of overlying strata movement and the dynamic response numerical simulation analysis is made.Get:(1) the magmatic rock this special strata exist,the gob overburden movement law of variation.(2) the presence of magmatic rock,rock stress,deformation and displacement of the change trend of the working face is revealed,develop in the rock and the redistribution of the stress process,working face support pressure and support resistance variability.