The invention discloses a single pile type supporting foundation for a tidal energy water turbine. The single pile type supporting foundation comprises a single pile foundation body and a supporting structure. The supporting structure is installed on the outer side of the single pile foundation body, the bottom of the single pile foundation body penetrates into the seabed, and the top of the single pile foundation body is arranged under the sea surface; the single pile type supporting structure comprises a lateral supporting arm, a supporting ring and a base, one end of the lateral supportingarm is connected to the outer wall of the single pile foundation body, the other end of the lateral supporting arm is connected with the supporting ring, the supporting ring is provided with a slideway structure, and the base can slide in the slideway structure and is fixed to the slideway structure after sliding to a certain position; and the tidal energy water turbine is connected to the base. The novel tidal energy supporting base structure with the combination of a large-diameter single pile and a multi-layer circumferential support is provided, and the adjustment of the position of the tidal energy water turbine installed is realized by the circumferential shiftable slideway structure, the stability of the supporting structure of the tidal energy water turbine is improved, the collection rate and collection range of ocean tidal energy are enhanced, and the development cost of a traditional pile-column-type tidal energy water turbine supporting structure is reduced.