The invention belongs to the technical field of steam-water separation and particularly relates to a steam dryer. The bottom of a guide vane is connected with the upper surface of a guide vane supporting circular plate, the top of the guide vane is connected with the lower surface of a base plate, and an opening is formed in the center of the base plate; the lower portion of a lower cylinder is connected with the upper surface of the base plate, and the upper portion of the lower cylinder is connected with lower surface of an annular plate; the upper surface of the annular plate is connected with the bottom of a drying vane which is enclosed by an upper cylinder, the upper portion of the upper cylinder is welded to a top plate, and the top of the drying vane is connected with the top plate; an opening formed in the center of the top plate serves as a steam outlet, and certain small holes are formed to serve as by-pass holes; and a drain pipe is connected with the base plate, and a water collecting box is formed by side plates, the base plate and the top plate. The steam dryer is high in critical speed, compact in structure and easy to machine and manufacture.