Abstract: The calculation method and dynamic characteristics of coupled parametric excitation and vortex excitation are investigated for top-tensioned risers. The analysis model of TTRs is presented considering the moving boundary conditions, and the vortex-induced response, coupled parametric excitation and vortex excitation vibration of TTRs in the shear flow are studied. The analysis method of dynamic response is proposed to research the influence of parametric excitation on VIV of the TTRs. The result shows that the VIV response of the TTRs contains the component of 1/2 sub-harmonic induced by parametric excitation, and that the parametric excitation has important significant for transverse vibration of TTRs.