The present invention relates to a method for manufacturing a battery stack cooling plate for an electric vehicle, the method comprising: a plastic working step for plastic working each of an upper plate and a lower plate which are made of a clad material and constitute a cooling plate; a preheating step for preheating each of the upper plate and the lower plate; a coating step for coating a flux on the upper plate and the lower plate; and a brazing step for heating the upper plate and the lower plate in a state where the clad materials of the upper plate and the lower plate are in contact with each other, so as to bond the upper plate and the lower plate together.