The aim of this study is to clarify the bond mechanism of Carbon Fiber Sheet (CFS) attached to concrete using epoxy resin and to propose the numerical methods which can simulate the bond behavior of CFS and its bond strength. A bond-slip-strain relation for CFS has been developed based on the bond characteristic which was clarified by means of experimental observation. A numerical method using the bon d-slip-strain relation can simulate the actual bond behavior. This paper also reports that a bond strength equation developed by the numerical analysis can predict the experimental results with good accuracy.