The invention discloses a high-power curved waveguide comprising a curved waveguide body. Two sides of the curved waveguide body are symmetrically provided with a liquid-cooling heat-dissipating liquid inlet tank and a liquid-cooling heat-dissipating liquid-outlet tank for passing a cooling liquid, and an output end of the liquid-cooling heat-dissipating liquid inlet tank communicates with an input end of the liquid-cooling heat-dissipating liquid-outlet tank. The curved waveguide body comprises a smooth wall horn, a circular polarizer, a transition section, a curved waveguide, a coupler and acircular waveguide elbow. An output end of the circular waveguide elbow is connected to an input end of the coupler, an output end of the coupler is connected to an input end of the curved waveguide,an output end of the curved waveguide is connected to the transition section, an output end of the transition section is connected to an input end of the circular polarizer, and an output end of thecircular polarizer is connected to an input end of the smooth wall horn. The cooling liquid is inputted into the liquid-cooling heat-dissipating liquid inlet tank from the input end of the liquid-cooling heat-dissipating liquid inlet tank, the cooling liquid flows through the curved waveguide body and then flows out through the liquid-cooling heat-dissipating liquid-outlet tank, the heat dissipation of the curved waveguide and the heat dissipation of the cooling liquid are achieved, and new interference is not brought to the curved waveguide.