With the development of offshore wind farm, large-scale and large-capacity, the wind power All-DC transmission system constructed by DC wind turbine has become one of the hotspots of offshore wind power generation technology because it can avoid the use of bulky power frequency AC transformer and solve the problem of reactive charging current caused by AC cable. Firstly, according to the different boost methods, the schemes of wind power All-DC transmission system are divided into two categories: boost device boost type and series boost type; Secondly, according to the different system structures, the boost type system scheme of the boost device is further divided into five system schemes: centralized boost type, two-stage boost type, machine end boost type, DC parallel type of the booster station and DC series type of the booster station. The series boost type system scheme is divided into four system schemes: direct series type, series-parallel type, parallel-series type and matrix type; Then it introduces the system structure, advantages and disadvantages of various schemes, analyzes and compares the characteristics of various schemes, and points out their application scenarios combined with the characteristics of various schemes; Finally, the main problems and development trend of wind power All-DC transmission system are summarized and prospected.