Overwater anti-collision device capable of alarming

The utility model discloses an overwater anti-collision device capable of giving an alarm, and relates to the technical field of anti-collision devices. The navigation mark comprises a navigation mark body and a limiting mechanism, the surface of the navigation mark body is sleeved with a connecting ring, a buoyancy ring is fixedly installed on the surface of the connecting ring, a floating air bag is fixedly installed on the inner wall of the buoyancy ring, and a plurality of hollow pipes are fixedly installed on the surface of the buoyancy ring. When the navigation mark is used, a worker places the navigation mark body in the buoyancy ring and limits the navigation mark body through the limiting mechanism, then the navigation mark is placed in water, the navigation mark can be normally used, when a ship collides with the surface of any contact ring, the insertion ring connected with the contact ring can be driven to slide on the inner wall of the corresponding hollow pipe, and therefore the navigation mark