A rotational structure applied to a rotational mop set is provided. The rotational structure comprises a rotating body, a rotating unit, and at least a pawl unit. The rotating body has at least a stopper. The rotating unit is rotatably assembled to the rotating body, and has a through hole. A spiral bar penetrates the through hole for driving the rotating unit along a first rotating direction or a second rotating direction. The pawl unit is corresponded to the stopper and rotatably assembled to the rotating unit for engaging with the stopper when the rotating unit rotates along the first rotating direction to drive the rotating body to rotate along the first rotating direction, and the pawl unit escapes from the stopper when the rotating unit rotates along the second rotating direction.