Floating valve is a new-style blowoutpreventer within the drill. The valve is open through which the drill fluid can circulate when drilling goes normally. The valve will close to prevent blowout when well kick or blowout happens. It can effectively prevent drill fluid flowing back and prevent sands flowing into the drill pipe to avoid blocking up. It is a specific tool for blowout preventing in drilling. The structure of floating valve is so scientific that it can avoid corruption and short lifetime which are the common problems of their kind to insure of the protection in the whole procedure of drilling.