Abstarct: In this research, the determination of mechanical stress intensity factor and electrical intensity factor in cracked piezoelectric materials and cracked FGP materials is studied. The numerical method used in this research is extended finite element method (X-FEM). The computer program is written in MATLAB that contain main program and some subprograms. Mechanical and electrical intensity factors in FG and FGP plates with central, edge and oblique crack are investigated after computational of mechanical displacements, electrical potential, also stresses and electrical siplacements. baxsed on results, the effect of mechanical load on electrical intensity factor and the effect of electrical load on stress intensity factor are inconsiderable. Also, analyzing the effect of crack angle, mechanical stress intensity factor mode I and electrical intensity factor decrease and mechanical stress intensity factor mode II decrases, first and finally increases with increasing of crack angle.