The work presented in this paper focuses on evaluating the rotational characteristics and capture efficiency of a novel variable guide vane wave energy converter (WEC). The rotation of the guide vanes under the action of waves drives the rotation of the vane wheel, generating electricity. The vane wheel always rotates in one direction, regardless of the rotation direction of the guide vanes. The optimal maximum turning angle of the guide vane is determined using a simplified model run with commercial CFD software , which is then validated by experimentation. Experiments were conducted on a 1:4 scale model using guide vanes set at the optimal maximum turning angle under conditions both with and without a generator. It is observed in these tests that the device intermittently pauses when the velocity of the water particles at the height of the vane wheel is less than 0.211 m/s under no-generator conditions. Capture efficiency is approximately 7% because of the short time, small area, and small range of the device for harnessing the wave energy. An electronic load with a resistance varying in the range of 1–500 Ω is then connected to the generator, and the working performance of the WEC is investigated. Finally, two alterations intended to improve the capture efficiency of the variable guide vane WEC are proposed and evaluated, and the capture efficiency of a scaled-up model is discussed.