Since carbon fiber reinforced plastic (CFRP) laminate has superior specific strength and stiffness as compared with metals, it has been increasingly applying to aerospace structures. It is, however, sensitive to an impact which causes a delamination in the laminate. The delamination strongly reduces the mechanical property of the laminate with difficulty of visual inspection. Simple structural health monitoring method is required to maintain the structural reliability of CFRP structures. Many researchers have been reported strain-sensing system of CFRP in which piezoresistivity of CFRP laminate is utilized. It is, however, not reported the delamination sensing. The delamination releases the residual stress in the laminate which was caused in the fabrication process. The delamination may be detected by measuring electric potential changes due to the release of residual stress. In this paper, FEM analyses are performed to investigate the applicability of the method for delamination detection in the quasi-isotropic CFRP laminates.