Abstract: Monopile is a widely-used foundation form for offshore wind power. The seabed conditions in the sea area of Guangdong，harsh environment loads，and continuous development into deeper seas have lead to the wider application of large-diameter monopiles in offshore wind farms in shallow water area. At present，the monopile foundation design in China mainly adopts the p-y curve method. This method is based on the test of small-diameter long flexible piles，which underestimates the stiffness and bearing capacity of large-diameter monopile pile-soil interaction and increases construction costs and construction difficulties. By comparing the mainstream monopile foundation design methods in Europe，an improved pile-soil interaction analysis and optimized design method for large-diameter monopile foundations in offshore wind power has been established. The key technology is based on the multi-spring model proposed by NGI，combined with the results of in-situ CPTU tests and geotechnical tests，which can more accurately simulate the pile-soil interaction effect and achieve refined design of large-diameter monopile foundations for offshore wind power.