The utility model relates to an automatic alkali preparation device for casein production. The automatic alkali preparation device comprises a flake alkali groove (1), a spiral feeder (2), a weighing scale (3), a water tank (4), an electromagnetic valve I (5), an PLC(programmable logic controller) automatic control module (6), a stirrer (7), an alkali dissolving tank (8), an alkali type liquid level meter I (9), an electromagnetic valve II (10), an alkali tank (11) and an alkali type liquid level meter II (12), wherein the spiral feeder (2) stably conveys flake alkalis to the weighing scale (3), the coordination between the spiral feeder (2) and the weighing scale (3) is finished by the PLC automatic control module (6), the alkali type liquid level meters are mounted on walls of the alkali dissolving tank (8) and the alkali tank (11), and a liquid level meter signal is transmitted to the PLC automatic control module (6) to finish automatic control.