The utility model discloses the needle provides a fixing bolt nut of demolising fast, includes bolt, nut and gasket at least, the bolt is become with screw set by the bolt head, screw rod and nut andthreaded connection, and screw rod and nut junction add and are equipped with the gasket. Borehole operation round trip in -process has been solved to this fixing bolt nut, when the well head installation is proclaimed oneself the blowout preventer or is prevented the junk device, works as the well head and incidents such as overflow, well kick appear, need demolish when proclaiming oneself the blowout preventer or preventing junk device, can demolish this bolt fast, reliably, has reduced the well control risk.