The present invention relates to a structure of positioning and fastening, particularly to a fast mounting and positioning fastener, including a supporting part located below the clamped object and an upper compressing part located above the clamped object. The supporting part is made by bending metal wire and forming into a shape of plane. One end of the metal wire extends freely to form a first free end, and the other end is a connecting end. The upper compressing part is formed by bending the metal wire as well. The upper compressing part includes a middle part connecting with the connecting end. The middle part extends from the connecting end to a position close to a center of the supporting part. The middle part and the supporting part is located in a same plane and the upper position of the middle part connects with a handheld part.