The principle of ultra-rapid-scanning Interferometer is introduced and a new kind of ultra-rapidscanning imaging interferometer based on the principle is provided. The imaging interferometer has a wider angle of field and higher scan efficiency. The character of the imaging interferometer is that it has a rotating planner reflector with an angle of inclination instead of the straight-line planner reflector in Michelson interferometer. The questions of lower scan efficiency and instability are well solved in Michelson interferometer.