Swimming pool cover

A swimming pool cover, comprising:

• a flexible cover layer, the flexible cover layer configured to completely cover a surface of a swimming pool;
• a flexible surrounding edge, the flexible surrounding edge extending downwardly from an outer edge of the flexible cover layer, so that the flexible surrounding edge is suspended on an outer side wall of the swimming pool;
• a flexible wrapping edge, the flexible wrapping edge being connected around a lower end of the flexible surrounding edge, and the flexible wrapping edge being provided with a plurality of fourth threading holes;
• a tightening wire, the tightening wire passing through the plurality of the fourth threading holes to attach the flexible wrapping edge to the outer side wall of the swimming pool;
• and
• a tightening device, wherein the tightening device is arranged on the tightening wire, and the tightening device is configured to adjust a tightening length of the tightening wire so that the flexible wrapping edge is able to be attached on the outer side wall of the swimming pool of different sizes;
• wherein the tightening device is a wire twister, the tightening device comprises a wire twister shell and a wire winding rod, the wire twister shell comprises an upper shell, a lower shell arranged opposite to the upper shell, a left shell and a right shell, the left shell and the right shell are connected to the upper shell and the lower shell and are arranged opposite to each other, two ends of the wire winding rod are inserted between the upper shell and the lower shell, and the wire winding rod is also connected to a rotating device, and the wire winding rod is configured to be rotated relative to the wire twister shell through the rotating device.