This study is the method of using the mechanical type to cut the substrate of the glass , under the circumstances that the glass surface is cut directly, probably produced 10¡ã20% of the depth of crack that is the thickness of glass, and then pulled the glass and split by mechanical stress , use the ANSYS and finite element method carry on relevant research and compare, survey the perfect cutting parameter to increase the yield in the future. This study is in order to find out the surface fracture stress distribution status after cutting and take advantage with the finite element method ,and compare with the result of median crack when glass substrate after cutting .It discuss with change parameter of the cutting pressure and Cutting depth ,than to compare with finite element method, it regard as discussing the quality after cutting to reduce the risk of surface defect.