Abstract: Taking the "Offshore Wind Power Flexible DC Transmission Demonstration Project in Guangdong " as an example, this study delves into the design and application effectiveness of a flexible DC transmission technology based on a "land-sea coordination" architecture. Engineering validation reveals that this solution offers significant advantages in addressing transmission corridor constraints, reducing system losses, and enhancing grid stability. It effectively resolves issues such as corridor limitations, economic inefficiency, and poor power quality, holding potential for promoting large-scale intensive offshore wind power development and grid integration in China.