Ocean wave is one of the biggest sources of renewable energy that is economically attractive. However, technology of harvesting wave power is relatively undeveloped compared to other renewable energy technologies. Finding optimal structures of wave energy converter (WEC) is still an open research problem. The idea of using Stewart platform as a WEC is for the first time proposed in this paper. Its key module is a Stewart platform, which is a parallel mechanism with six degrees of freedom, used to convert the motion induced by waves to the prismatic motions of multiple hydraulic/ pneumatic cylinders. The proposed new type WEC can be used in the offshore wave power generation systems and put in any place where there exist roaring waves.The mathematical model has been set up and the numerical simulation has been performed to verify the effectiveness of the proposed converter. The simulation results show that more energy can be generated by this new type of converter than other existing WECs.