Abstract: Based on traditionally external prestressed reinforcement approaches, the paper proposes a new reinforcement technique, external prestressed cable of tilted belly poles. Taking the simply-supported beam as the object to be reinforced, the cable behavior is modeled. The formulas for the cable deformation and tension forces are obtained. The relations between cable deformation, tension forces and the applied load are investigated in this paper, showing that: (1) the cable configuration is of the form of ellipse; (2) the maximum horizontal tension force of the cable occurs at the mid-span of the simply-supported beam, and the minimum horizontal force occurs at the anchor point. Such a stress characteristic makes fully use of the cable advantage of high tensile capacity, as well as reduces the unfavorable effects of cable horizontal force on the beam. Under the action of the radial uniform load, the nonlinear relationship between the cable length incensement and the deflection incensement is observed. The iterative calculation algorithm prefers small load-step, the smaller the load-step, the higher the precision.