The utility model discloses a spray head replacing device comprising an installation sleeve body which is sleeved on a water supply branch pipe, a fastening device which is used for detachably fastening the installation sleeve body on the water supply branch pipe, and a clamping piece which can extend into the installation sleeve body and is used for clamping a firefighting spray head from one side surface, wherein the upper part of the clamping piece is provided with a slot in which the firefighting spray head is inserted laterally; an installation part which is arranged at the upper part of the firefighting spray head and is to be connected with the water supply branch pipe extends up to go out of the clamping piece; two opposite surfaces of a fixed part in the middle of the firefighting spray head are positioned between the two opposite side walls of the slot; the middle of the clamping piece is provided with an annular bulge; the side wall of the annular bulge and the inner wall of the installation sleeve body are provided with threads which are matched with each other; the lower part of the clamping piece extends down out of the installation sleeve body; and the side wall of the lower part, (extending out of the installation sleeve body) of the clamping piece is provided with an installation surface for installing a wrench. The spray head replacing device can be used for finishing quick repair of the firefighting spray head and is capable of saving a large amount of water resources, thereby bringing about high economic and social benefits.