NOVELTY - A rectifying process for extracting xenon-krypton from liquid oxygen comprises collecting the extracted liquid oxygen in a storage tank, enabling it to enter a rectification column system, removing impurity from the liquid oxygen by a rectifying tower and a nitrogen washing tower in the rectification column system, and extracting xenon-krypton.    USE - The rectifying process is useful for extracting xenon-krypton from liquid oxygen (claimed).    ADVANTAGE - The rectifying process is high in xenon-krypton recovery rate, safe and reliable in the whole process, excellent in economic benefit, improved in device running safety performance, simple to operate, and wide in field of application. Moreover, it saves the device investment cost and energy consumption and achieves continuous and stable production operation.    DETAILED DESCRIPTION - A rectifying process for extracting xenon-krypton from liquid oxygen comprises collecting the extracted liquid oxygen in a storage tank, enabling it to enter a rectification column system, removing impurity from the liquid oxygen by a rectifying tower and a nitrogen washing tower in the rectification column system, and extracting xenon-krypton; where it specifically comprises: (a) introducing liquid oxygen to a first stage rectifying tower in the rectification column system to rectify and separate it, and obtaining oxygen on a tower top and xenon-krypton concentrated solution at a tower bottom; where the operating pressure in the first stage rectifying tower is 0.11-0.4 MPa, preferably 0.21 MPa; and the number of tower plate is 3-20, preferably 15; (b) pouring the xenon-krypton concentrated solution from (a) into the nitrogen washing tower, introducing liquid nitrogen from the upper part of the tower top as solvent and introducing nitrogen from the tower kettle to control the amount of uprising gas in the tower, adsorbing the xenon-krypton concentrated solution in an absorption tower to obtain nitrogen-oxygen mixture discharged from the tower top, discharging the obtained xenon-krypton concentrated solution by the tower kettle; where the operating pressure in the nitrogen washing tower is 0.4-0.8 MPa, preferably 0.6 MPa; and the number of tower plate is 20-40, preferably 28; (c) pouring the xenon-krypton concentrated solution from (b) to a second stage rectifying tower and obtaining nitrogen on the tower top and xenon-krypton secondary concentrated solution at the tower kettle; where the operating pressure in the second stage rectifying tower is 0.4-0.8 MPa, preferably 0.55 MPa; and the number of tower plate is 5-22, preferably 18; (d) pouring the xenon-krypton secondary concentrated solution from (c) to a third stage rectifying tower and obtaining nitrogen and methane on the tower top and xenon-krypton third concentrated solution at the tower kettle; where the operating pressure in the third stage rectifying tower is 0.4 to 0.8 MPa, preferably 0.5 MPa; and the number of tower plate is 25-60, preferably 40; (e) pouring the xenon-krypton third concentrated solution from (d) to a fourth stage rectifying tower to rectify and separate it, and obtaining krypton concentrate on the tower top and xenon concentrate at the tower bottom; where the operating pressure in the fourth stage rectifying tower is 0.1-0.6 MPa, preferably 0.4 MPa; and the number of tower plate is 5-26, preferably 15; (f) pouring the krypton concentrate from the tower top in (e) to a fifth stage rectifying tower to rectify and separate it, and obtaining pure krypton product having mol content that is not less than 99.999%; where the operating pressure in the fifth stage rectifying tower is 0.2-0.7 MPa, preferably 0.34 MPa; and the number of tower plate is 7-23, preferably 12; (g) pouring the xenon-containing concentrate from the tower kettle to the sixth stage rectifying tower to rectify and separate it, and obtaining xenon-containing fluid having mol content that is not less than 99.999%; where the operating pressure in the sixth stage rectifying tower is 0.1-0.7 MPa, preferably 0.43 MPa; and the number of tower plate is 50-100, preferably 88; and (h) pouring the xenon-containing fluid from the tower top to the seventh stage rectifying tower to rectify and separate it, and obtaining pure xenon product having mol content that is not less than 99.999%; where the operating pressure in the sixth stage rectifying tower is 0.1-0.7 MPa, preferably 0.38 MPa; and the number of tower plate is 5-30, preferably 27.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of the device used in the rectifying process for extracting xenon-krypton from liquid oxygen.