Abstract: In order to study the nonlinear mechanical properties of concrete beams with carbon fiber reinforced composite (CFRP) rebars，a finite element analytical model of the beam with CFRP rebars was set up combined with corresponding nonlinear theories. The nonlinear whole course of four beams with prest ressed CFRP rebars was analyzed and the regularities of the stresses of CFRP rebars，GFRP rebars and common steels were studied. Compared with the experiment results，the calculations are in good agreements with the test results. The result shows that the nonlinear properties of the concrete are properly considered on the basis of the smearing crack model，Owen yielding criterion and Hinton crushing theory. The prestressed CFRP rebars are efficiently modeled by combined elements and the corresponding computational procedure for nonlinear whole course analysis is of satisfying correctness. CFRP rebars are still in an elastic status when the beam reaches the ultimate loads because of high strength property. Compared with the specimens which have common steels in the bottom，GFRP rebars are always in the elastic status during the whole course.