Abstract: The present invention provides a high-pressure-water toothbrush and a U-shaped jet-washing groove structure thereof, comprising: a handle and a U-shaped jet-washing groove provided at an end of the handle. The U-shaped jet-washing groove structure has a first sidewall and a second sidewall facing the first sidewall, and each of the first sidewall and the second sidewall has an inner wall surface provided with a plurality of nozzles. By the implementation of the present invention, the insides and outsides of the teeth surfaces and teeth gaps can be simultaneously flush for the purpose of quick and effective to cleaning the teeth.