Abstract: To address the pronounced responses of offshore floating photovoltaic (FPV) platform to wave-induced motion and the strong environmental dependence of standalone photovoltaic power generation output, an integrated FPV system incorporating oscillating water column (OWC) devices is proposed, of which the OWC devices are symmetrically arranged around a pontoon-truss-type FPV platform, enabling additional wave energy capture while regulating the hydrodynamic response of the floating platform. Based on potential-flow theory and time-domain coupling method, a numerical model coupled hydrodynamics and energy capture is established, in which platform motions, OWC water-column responses, equivalent power take-off (PTO) damping and mooring constraints are taken into account. The motion responses and wave energy capture characteristics of the FPV-OWC integrated system after the introduction of OWC are analyzed, and the effects of OWC chamber diameter and wave incidence angle on the overall system performance are further studied. The results show that the introduction of OWC devices has a minimal impact on the overall heave response of the platform and does not significantly change the dominant heave restoring mechanism, but it can effectively suppress the low-frequency response of the platform under both pitch and roll degrees of freedom. The wave energy capture of the integrated system is mainly concentrated in the high-frequency operating range. Owing to stronger local wave excitation, the up-wave OWC units generally exhibit a higher energy capture capacity than the lee-side units. Within the investigated range, increasing the chamber diameter can effectively enhance the suppression of platform heave response in the low-to-medium frequency range and improve the wave energy capture performance within the high-frequency operating range. However, it does not significantly broaden the effective energy-capture bandwidth, indicating that a larger chamber diameter can mainly increase the intensity of energy conversion within the primary operating band. Under the oblique wave condition, the integrated system exhibits an even better energy capture performance. When the wave incidence angle increases from 0° to 45°, the surge and pitch responses of the platform decrease, while the total mean power of the OWC array within the primary operating band increases and the stability of the integrated system is improved to a certain degree. This study can provide a reference for the structural design and parameter optimization of offshore FPV-based multi-energy complementary systems.