The invention discloses a rotatable cup brushing device. The cup brushing device includes a cylindrical rotating body, and upper cover plate of the rotating body is provided with a circular central through hole I which can allow a screw rod to pass through, the rotating body is provided with brushing hair, and the rotating body further includes a rotating device; the barrel-shaped rotating deviceis located in the rotating body, an upper cover plate of the rotating device is provided with a rectangular central through hole matched with the cross section of the screw rod, the outer surface of the side wall of the rotating device is provided with several uniformly distributed connecting rods by using the axis of a circular central through hole II as an axis, up-and-down movement of the screwrod makes the rotating device rotate, and thus the brushing hair is driven to rotate. Only through repeated stretching and squeezing action, users can clean cups, the cup brushing device is compact is in structure and easy to operate, and no injury is caused to joints of the human body.