The invention discloses a bottle cap capable of being sucked. The bottle cap capable of being sucked comprises a bottle cap shell and a flexible straw, and further comprises a limiting ring, a rotating wheel, a driving wheel, rolling wheels and a stop dog, wherein the rotating wheel is arranged in the bottle cap shell, the limiting ring is fixed in the bottle cap shell, and the stop dog is fixed on the limiting ring; and the rolling wheels and the driving wheel are arranged in the limiting ring, the rolling wheels are connected with the limiting ring, the rolling wheels are connected with thedriving wheel, and the driving wheel is connected with the rotating wheel, the flexible straw is attached to the inner side of the stop dog, meanwhile, the flexible straw is fixed between the rollingwheels and the stop dog. According to the bottle cap, the rolling wheels and the stop dog are used for clamping and extruding the flexible straw, liquid in a bottle is sucked into the straw and flowsin the straw, so that the quantitative liquid can be sucked out, the structure is simple, and the use is convenient.