In recent years, with the further improvement of offshore wind power technology and construction level, and the continuous improvement of electricity price policy, China's offshore wind power has developed rapidly. As a major coal consuming Province, Shandong has great pressure on the transformation of energy structure. Using the abundant wind energy resources along the coast of Shandong to speed up the development of new energy industries such as wind power can fundamentally optimize the energy structure and reduce coal consumption. The large-scale development and adoption of large- capacity wind turbines in offshore is an important way to improve the economy of offshore wind power transmission. This paper analyzes three different transmission schemes of offshore wind power AC transmission, conventional DC transmission and flexible DC transmission. The technical and economic comparison of three different transmission technology is presented.