The two-mode nonlinear response of suspended cables subjected to superhamonic resonances with one-to-three internal resonances was investigated.Firstly,the Galerkin method was used to discrete the governing equation to a discrete form of the equations of motion. And the method of multiple scales was applied to attack the equations of motion leading to averaging equations. At last the equilibrium solutions of averaging equation were examined. Also the effects of the sag-to-span ratios on the frequency-response curves, horizontal tensions and the time history were discussed.