The breakwaters are utilized for absorbing wave energy to provide suitable berthing conditions for the harbors. The caisson breakwater can be modified as the air chamber of the Oscillating Water Column (OWC)- Wave Energy Conversion (WEC) facilities. In the present paper, the integrated structure of Caisson breakwater- OWC chamber is practically designed. The experiments are performed in the wave flume to obtain the oscillating amplitude of inner water column inside the chamber, which are usually employed to demonstrate the operating performance of the OWC chamber. A numerical wave tank based on the two- phase VOFmodel is established to generate 3D incident waves. The numerical wave tank consists of the continuity equation, Reynolds-averaged Navier- Stokes equations and two-phase VOF volume fraction equations. The standard k-e turbulence model, finite volume method, NITA-PISO algorithm and dynamic mesh technique are employed. The numerical resultsare compared and validated by the above corresponding experimental data. The effects of several incident wave conditions and shape parameters on the wave energy converting efficiency and performance of integrated system are investigated.