The invention provides a multistage cold-rolling device for copper bar production. The device comprises a frame, a cold roll, a first driving mechanism, a first setting table, a second setting table, a feeding mechanism and a material receiving mechanism, wherein a plurality of annular semi-grooves which are different in groove depth are axially formed in the periphery of the cold roll at intervals; a plurality of first forming semi-grooves which are different in groove depth are formed at intervals on one side, close to the cold roll, of the first setting table, and the quantity of the first forming semi-grooves is consistent with that of the annular semi-grooves and the forming semi-grooves and the annular semi-grooves are spliced one by one to form circumferentially closed first cold-rolling grooves different in diameter; a plurality of second forming semi-grooves which are different in groove depth are formed at intervals on one side, close to the cold roll, of the second setting table, and the quantity of the second forming semi-grooves is consistent with that of the annular semi-grooves and the forming semi-grooves and the annular semi-grooves are spliced one by one to form circumferentially closed second cold-rolling grooves different in diameter. The device provided by the invention can be used for machining copper bars different in size, and is high in work efficiency and wide in application range.