According to Hengjin Mine 9108 fully mechanized caving face roof cutting blasting scheme, based on the analysis of the pre-splitting blasting theory and geological condition of the working face, the main parameters of the pre-splitting blasting, blasting and the radius calculation formulas of hole spacing, then the ANSYS/ LS-DYNA numerical wave observation should be developed from the equivalent stress nephogram and crack propagation analysis, crack area radius value from the pressure time history curve, it was suitable for underground roof caving blasting parameters, thereby improving the fully mechanized working face at the beginning of the initial mining rate.