The invention relates to a fastener for fixing scaffolds and an assembling/disassembling tool. A rapidly assembled/disassembled fastener is composed of an upper-half fastener and a lower-half fastener, the upper-half fastener is in damped hinge with the lower-half fastener by rivets, and the structures of the upper-half fastener and the lower-half fastener are the same; the upper-half fastener comprises a base, a cover plate, a draw bar, a lock lever and a safety lock; the left end of the base is hinged with the left end of the cover plate, and the right end of the cover plate is provided with a U-shaped open slot; a safety-lock clamp, a washer of the safety lock and a locking bit are fixed on the upper surface of the cover plate; the washer of the safety lock is hinged with the safety lock by a pin shaft and a torsional spring; when moving anticlockwise, the safety lock can be hung by the safety-lock clamp, thereby facilitating the operation of the lock lever; the right end of the base is hinged with the lower end of the draw bar, the upper end of the draw bar is eccentrically hinged with an arc head at the lower end of the lock lever, the draw bar is embedded in the U-shaped open slot of the cover plate, and the arc head at the lower end of the lock lever is pressed on the upper right end of the cover plate; and the locking bit is provided with a stepped locked groove, and the opening of the locked groove is shielded by the safety lock. The assembling and disassembling of the fastener are time-saving and labor-saving without fearing of being exposed to the sun and rain.