The installation methods used in offshore wind farm around the world were summarized, and the process of split installation, the set necessity and principles of assembly base were analyzed. 8 kinds of typical land-based assembly programs and the assembly technology of main parts were summarized. An installation method was proposed by sitting of the diving boat. The diving installation ship was made by installing a crane, and was located in the seabed during the operation to hoist the turbine components. The installation method is suitable for offshore wind farm construction. The application of the installation method in the test turbine project of Jiangsu Xiangshui offshore wind farm was introduced in the paper finally.