The invention discloses a jet stirrer for mechanical stirring and desulfurizing of molten iron. The jet stirrer comprises a rotating shaft and stirring blades arranged at the lower end of the rotating shaft and uniformly distributed along the circumferential direction of the rotating shaft, wherein the rotating shaft consists of a metal hollow shaft and a refractory material working lining compounded on the outer side of the metal hollow shaft; an air cooling pipe is arranged in the cavity of the metal hollow shaft; the lower end of the rotating shaft is provided with a jet channel communicated with the air cooling pipe; and the jet channel is positioned between adjacent stirring blades. In the jet stirrer, cooling gas is jetted from a puff port into a stirring center vortex to drive a desulfurizer in a forced vortex area of a stirring center to move relative to molten iron, so that the mixing and dispersing of the desulfurizer in the forced vortex area of the stirring center in the molten iron is realized, and the desulfurizing reaction dynamic condition in the area is improved. Meanwhile, the retention and bonding of desulfuration residues between adjacent blades can be restrained, the effective acting areas of the stirring blades are increased, the dry slag cleaning and maintaining amount of the stirrer is reduced, and the mechanical stirring and desulfurizing production capacity of the molten iron and the utilization ratio of the desulfurizer are increased.