An ocean-current generator based on macro fiber composite (MFC) is proposed, and the performance of the generator is analyzed. Firstly, the cantilever structure is taken as the research object to analyze the influencing factors of performance of piezoelectric generation. The laws of influences of substrate materials, thickness, frequency, displacement excitation, and single/double crystal structure are researched. Then, an ocean-current generator based on MFC is designed according to the performance analysis results. Finally, the electricity generation performance of the ocean-current generator is analyzed. The maximum output power of the generator is 9.31 W at a rotor speed of 500 r/min, which can meet the power requirements.