The invention discloses a device for leaching manganese ore to remove iron, and an iron removing method thereof. Air is introduced into a stirring container in an impulse form to assist removing iron from the manganese ore. The device mainly comprises a frequency conversion system, a transmission system, an air distribution system and a stirring paddle system. An impulse air jet stirring system adopted achieves the double aims of increasing oxygen concentration in ore pulp and reducing a stirring dead zone; the pyrolusite is saved in the iron removing process; the manganese leaching time is greatly shortened to 4 hours through the air distribution system; and the work efficiency is improved by 60 percent.