The invention discloses a quickly-assembled nut. The quickly-assembled nut comprises a first nut sleeve buckle, a second nut sleeve buckle, locking shaft sleeves, a first guide pin, a first spring, balls and a second guide pin. When the quickly-assembled nut is used for conducting fastening, an operator can manually knead the first nut sleeve buckle and the second nut sleeve buckle together so as to lock the quickly-assembled nut. The quickly-assembled nut can be unlocked by manually pressing a pressing part of the first guide pin and exerting the force for separating the first nut sleeve buckle from the second nut sleeve buckle. The technical problem is solved by overcoming the defects that existing nut and bolt connection operation is complex and wastes time, and the quickly-assembled nut is easy and convenient to use and capable of achieving rapid nut and bolt connection.