Abstract: Marine power generation technology is conducive to meet electricity demand in a clean and green way. According to study on distribution and development of tidal, wave, tidal current, thermal and osmotic energy, key technologies of marine power generation are discussed in detail. Development obstacles of research, policy and environment are listed. Based on introduction of marine power development pathway in United States, development models and marine energy utilization methods in China are discussed. Finally, key technology road maps are proposed in different time periods.