The utility model discloses a self -closing skylight of cold passageway of computer room of data center, it includes that cabinet top support piece, base frame put up and revolving frame, the base frame frame is including long edge and short edge, be equipped with on the long edge and be used for pinning revolving frame's magnetic force lock, revolving frame pass through the rotation axis with short edge coupling, the rotation axis rigid coupling in revolving frame, the rigid coupling has hub connection spare on the rotation axis, be equipped with electric telescopic handle on the short edge, electric telescopic handle's flexible end with be equipped with wire rope between the hub connection spare, when during the shrink of electric telescopic handle's flexible end, revolving frame is in hub connection spare drives down towards being close to the direction of magnetic force lock is rotated. The utility model discloses a self -closing skylight has simple structure, low in manufacturing cost, can adjust opening the angle, opening advantage fast, that mechanical properties is good of skylight.