Abstarct: Ocean is one of the renewable sources of energy that can supply part of the world's energy needs and thus reduce the rate of consumption of fossil fuels and other non-renewable resources. The wave energy can be converted to electricity or other forms of usable energy. Therefore, it is important to achieve an efficient power transmission system. To achieve this goal, major devices in this field are analyzed. The recent study was conducted with the purpose of simulation and analysis of oscillating wave surge converter with the idea that in the Caspian Sea should be used. Oscillating Wave Surge Converters (OWSCs) are efficient devices for extracting power from sea and ocean waves. This converter is placed on the foundation at sea bed and rotated around a joint due to collision of wave. In the recent modelling, the Navier–Stokes equations are discretized using the Finite Volume method with the Volume of Fluid (VOF) approach for interface of water and air. Waves are generated with piston, rotational and stokes second order wave maker. In order to model oscillating flap, the dynamic mesh method is applied. The simulation were conducted for fixed and rotary flap and results have been evaluated for various parameters such as water depth, wave height and flap density. Also, the results of the wave converter have been performed for various wave stations of the Caspian Sea. By comparing the results of this research with experimental and numerical data, it is shown that results are precised and accurated. The results show that with increasing wave height, wave power and rotation of the flap are increased. Also with decreasing water depth, buoyancy force and amplitude of rotation are increased.