Floating ball ventilation device capable of preventing liquid from flowing backwards

The utility model provides a floating ball ventilation device for preventing liquid from flowing backwards, a closed cavity of the floating ball ventilation device is divided into a first cavity and a second cavity from bottom to top by a contact baffle, a floating ball is arranged in the first cavity, and a contact hole matched with the cambered surface of the floating ball is formed in the center of the contact baffle; the side wall of the first cavity is communicated with a first inlet pipe, the side wall of the second cavity is communicated with first outlet pipes, the first inlet pipe is communicated to the liquid cabin cabinet through ventilation branch pipes, each first outlet pipe is communicated to a ventilation main pipe, and the end part of the ventilation main pipe is connected with a ventilation head; during normal ventilation, the floating ball falls to the bottom position under the action of gravity, and air flows to the ventilation main pipe from the ventilation branch pipes to realize normal