The invention discloses a method and product for improving microchannel plate soft X-ray-extreme ultraviolet ray imaging performance. The method includes the steps that gaseous aluminium trimethide serves as an aluminum source, gaseous deionized water servers as an oxygen source, high-purity nitrogen serves as carrier gas and cleaning gas, an atom layer deposition system is utilized, and an aluminum oxide film is deposited on a square-hole microchannel plate made of lead-bismuth glass; and solid iridium acetylacetonate serves as an iridium source, metal iridium reduction is conducted with high-purity oxygen as an oxygen source, the high-purity nitrogen serves as the carrier gas and the cleaning gas, the atom layer deposition system is utilized, and the iridium film is deposited. Compared with an untreated microchannel plate, according to an aperture inner wall reflection increasing film of the square-hole microchannel plate manufactured through the method, the iridium serves as the metal reflection increasing film, and reflection efficiency is improved remarkably, so that the light intensity efficiency of the microchannel plate in the soft X-ray-extreme ultraviolet waveband imaging process can be improved effectively. By means of the method, the performance of the square-hole microchanel plate is improved, and application of the microchannel plate in a grazing incidence imaging system such as an X-ray telescope is further promoted.