The floating ring of the floating oil seal maintains a certain gap between the rotating shaft and can float freely, but it cannot rotate together with the rotating shaft. It can only perform radial slip floating and maintain a certain eccentricity with the center of the shaft under the action of gravity. When the rotating shaft rotates, the sealing liquid is input from the outside of the floating oil seal to form an oil film at the gap between the rotating shaft and the floating ring. Due to the action of the oil wedge power generated when the shaft rotates, a certain oil film pressure is maintained in the oil film, so that the floating ring can automatically maintain "centering" with the center of the shaft, thereby greatly reducing the amount of clearance and effectively realizing the fluid medium leaky seal.