Abstarct: t Considering the importance of energy in today's world, studies on new methods of energy extraction, especially renewable energies, are increasing. This research aims to optimize a mechanism used to harvest the vibration energy of sea waves. For this purpose, a five-bar flexible mechanism was selected and simulated in COMSOL software. After validating the simulation by comparing it with previous research, the dimensional optimization of the mechanism was carried out to maximize the output displacement. The optimization was examined in three cases and with different design variables, and the highest amount of displacement in the output of the mechanism was achieved in conditions where the design variables included the length of the arms, angles, and dimensions of the joints. Then, the manufacturing process of the optimal mechanisms was carried out using a PMMA sheet with a thickness of 8 mm, and the samples were tested. A piezoelectric patch was used to extract energy and an electromagnetic actuator was used to test the mechanism. After conducting the experiments, the displacement amplification rate in the optimal mechanism of the third mode was 19.3 times, an increase of 72% compared to the previously manufactured sample. This increase in displacement was achieved at lower mechanical stress in the joints. The highest mechanical stress in the joints of the mechanism was 17 MPa, which was determined by examining and comparing this stress with the numbers in the mextallurgical Laboratory declaration, which showed that the mechanism had this efficiency at 30% of the allowable stress.