<p>This paper establishes a 1:250 scale model to experimentally investigate the nonlinear dynamic behaviors of a cable-stayed bridge based on the Xiangshangang Bridge. Firstly, the experimental model and some necessary instruments are introduced. Modal analysis is then carried out and the physical parameters of the cables are determined. Subsequently, the nonlinear vibrations of the experimental model are studied by applying a harmonic excitation. In this way, rich out-of-plane and in-plane nonlinear behaviors are uncovered based on a detailed analysis of the forced vibration and superharmonic resonance, especially the superharmonic resonance of the out-of-plane modes. The experimental results reveal the possibility of the occurrence of higher-order superharmonic resonances. Specifically, higher-order superharmonic resonance of the in-plane and out-of-plane modes may be triggered under the external excitation, such as 6:1, 7:1, or even 8:1 superharmonic resonance of the in-plane modes and 2:1, 3:1, or even 4:1 superharmonic resonance of the out-of-plane modes.</p>