The invention discloses a modular cab detachably mounted on a shunting locomotive, solving the problems of complex structure, high cost, inconvenient assembly and disassembly and cannot guarantee theconnection strength of the cab main body in the prior art. The modular cab detachably mounted on a shunting locomotive comprises a cab main body, a bottom beam, a mounting beam and a mounting seat. The bottom beam comprises four channel steels and four sealing plates, and the top surfaces of the four channel steels are respectively welded with the bottom periphery of the cab main body, and the four sealing plates are respectively welded in the notches of the four channel steels, and the four sides of the bottom beam mounting beams are respectively located in the notches of the four channel steels, and the top surfaces of the four sides of the bottom beam mounting beams are respectively in contact with the bottom surfaces of the four sealing plates; four mounting upper seats are respectively welded on the two end outer sides of two channel steels on both sides of the bottom beam, and four mounting lower seats are respectively welded on the frame of the shunting locomotive, and each mounting lower seat is inserted into the corresponding mounting upper seats and detachably connected by bolts. The invention has lower manufacturing cost, is convenient to disassemble and assemble, and can effectively guarantee the connecting strength of the cab main body.