The invention discloses a high-power radial line sealed window which mainly solves the problem in the prior art that a mature sealed window aiming at a radial line is lacked and technical development requirements cannot be met. The high-power radial line sealed window comprises a radial line upper plate, a radial line lower plate, a radial line installed between the radial line upper plate and the radial line lower plate, a coaxial waveguide vertically connected with the radial line lower plate, a conversion cone with the upper end fixed on the radial line upper plate and a ceramic ring located between the radial line upper plate and the radial line lower plate, on the outer side of the conversion cone and coaxial with the coaxial waveguide. An inner conductor is arranged in the coaxial waveguide at the center position, and the inner conductor is connected with the lower end of the conversion cone. By means of the scheme, the window achieves the aims of being small in reflection, high in transmission efficiency, high in power volume and suitable for the radial line, and has high practical value and popularization value.