<p>This article uses analytical methods to study the nonlinear vortex-induced resonance characteristics of fluid-conveying offshore pipelines under supercritical and subcritical mechanisms, as well as the nonlinear resonance behavior under the combined action of vortex excitation and parametric excitation. Considering the geometric large deformation of slender flexible pipeline structures, the van der Pol equation in the semi empirical model is used to simulate hydrodynamic loads. At the same time, the motion of the floating structure connecting the pipeline under wave action is introduced into the fluid–structure coupling dynamic model in the form of axial tension that varies with the time. The partial differential equation of vortex-induced vibration (VIV) for fluid-conveying pipelines is truncated into an ordinary differential equation using the Galerkin method. Then, the nonlinear dynamic behavior and stability of the fluid–structure coupling system of VIV in offshore pipelines are analyzed using the method of multiple scales and nonlinear bifurcation theory. The influences of flow velocity, axial excitation, and vortex shedding frequency on the nonlinear resonance characteristics of fluid- structure coupling in offshore pipelines are studied. This study has important guiding significance for reducing pipeline fatigue damage caused by vortex-induced resonance in offshore oil pipelines.</p>