The invention provides a high-gain ultra-wideband corrugated double-ridge horn antenna with a loaded lens and belongs to the technical field of microwave antennas. The high-gain ultra-wideband corrugated double-ridge horn antenna is used for solving the problem that the double-ridge horn antenna is low in gain, and a high-frequency directional diagram is disintegrated. The high-gain ultra-wideband corrugated double-ridge horn antenna comprises a coaxial feed connector (1), a rectangular waveguide (2), a corrugated horn (3), a double-ridge waveguide (4) and the dielectric lens (5). The dielectric lens (5) of a hyperbolic structure is arranged at the position of a front port of the corrugated horn (3), the focus of the dielectric lens (5) coincides with the center of an antenna feed, a rear port of the corrugated horn (3) is connected with the rectangular waveguide (2), and the double-ridge waveguide (4) is arranged in the corrugated horn (3). The coaxial feed connector (1) is installed at the upper portion of the rectangular waveguide (2), and plane corrugations are arranged on the surface of the rear portion of the inner side of an upper metal plate (7) and the surface of the rear portion of the inner side of a lower metal plate (7). The high-gain ultra-wideband corrugated double-ridge horn antenna has the advantages that the ultra wide band, the high gain and the stable directional diagram are achieved in the 1-18 GHz area, and the high-gain ultra-wideband corrugated double-ridge horn antenna is suitable for the fields of electromagnetic compatibility tests, reflector antenna feed sources, ultra wide band radars and the like.