The invention relates to a rock-socketed single pile foundation through offshore wind power and a construction method of the rock-socketed single pile foundation. The rock-socketed single pile foundation comprises a steel pipe single pile which is positioned in the center, wherein the lower end of the steel pipe single pile is inserted into a seabed, and the upper end of the steel pipe single pile is positioned above the sea level; a fan tower cylinder is mounted at the upper end of the steel pipe single pile, and a plurality of steel pipe grouting piles which are fixedly connected to the steel pipe single pile are arranged at intervals at the internal circumambient part or the periphery in the steel pipe single pile; the lower ends of the steel pipe grouting piles are inserted into the seabed, and the upper ends of the steel pipe grouting piles are positioned above the sea level; the inner parts of the lower ends of the steel pipe grouting piles are grouted with concrete socketed piles of which the lower ends penetrate through the lower ends of the steel pipe grouting piles to be embedded and fixed in a baserock layer of the seabed. According to the rock-socketed single pile foundation disclosed by the invention, the difficult problem that at current, in China, full cut-off sock-socketed construction of large diameter pile foundation cannot be realized is effectively solved, and besides, the horizontal load bearing capacity and the antidumping capacity of the pile foundation are improved; the dynamic response of infrastructures is reduced, the application scope of the single pile foundation is enlarged, and the single pile foundation disclosed by the invention has a high application value.