To enhance the usable life of existing building, a sterengthening method with bonding CFRP plates has been developed by authors. The CFRP plates is high-strength (2100MPa) in longitudinal normal stress. The composite of steel bonding CFRP may easily peel out under tensile loading because shear bonding stress is concentrated at the edge of CFRP Plates. In this paper, tensile loading tests of composite of steel bonding CFRP plates were performed to clarify effect on unbonded area near edge of CFRP. Also, F.E.M. was performed to investigate the effect on low stiffness adhesive area near edge of CFRP Plates. The results showed that to improve the yield strength as the effect on unbonded area near edge of CFRP. Also, it showed the possibility that use a low stiffness of the adhesive area near edge of CFRP can be improved than unbonded area near edge of CFRP.