China is one of the largest energy consumers in the world. Excessive consumption of coal and other primary energy causes serious environmental pollution and energy crisis. China must wean from the over-reliance on coal and needs to make great efforts to develop clean and efficient renewable energy. In recent years, offshore wind energy has been developing rapidly with the advantages of not taking up land resources and high utilization rate. By the end of 2012, the total installed capacity of offshore wind power was 389.6 MW in China. The planning capacity will be 5 GW by 2015 and 30 GW by 2020. Compared to onshore wind power, the development of offshore wind power is facing some new problems and challenges, for example power transmission, offshore harsh natural environments, multi-sectoral coordination and management, and so on. This paper firstly analyzes the irrationality of China's energy consumption structure and the necessity for developing offshore wind power. Secondly, an overview of offshore wind farm access, AC (Alternating Current) and DC (Direct Current) transmission technologies and offshore wind turbine control strategies are given. The development status and future plans of offshore wind power are also introduced. Finally, we analyze the existing problems and obstacles during the construction process of offshore wind farms from three aspects, including technical, economic, and national policies. And some corresponding recommendations to accelerate the development of offshore wind farm are also proposed.