Shear strength of concrete beamss reinforced with FRP was studied through experiment and analysis. The effect of stiffness of longitudinal tensile reinforcement on the diagonal tension failure strength was calculated using the extended modified compression fields theory, and the evaluation method was proposed based on the analytical results. Furthermore, shear strength of the beams which fail due to the rupture of FRP stirrups was well evaluated by considering the lower stiffness and the strength reduction of FRP at bent corner.