The utility model discloses an air curtain descaling device of a rolling mill. The air curtain descaling device comprises a plurality of high-pressure air pipelines (1), and any one of the high-pressure air pipelines (1) is connected with a plurality of nozzles (2) used for purging the surfaces of rolled pieces (3). The air curtain descaling device has the advantages of simple structure, low equipment investment, few auxiliary devices, stability in running and the like and is quite applicable to production lines with small workshop spaces and limited water treatment capacity.