The utility model discloses a wedge and pneumatic linkage fixture which comprises a fixture frame body. A locating pressing plate is arranged on a platform top plate of the fixture frame body in an assembling mode, wherein the locating plate can prevent a workpiece from moving up and down. At least one pair of locking pressure heads are arranged on the two side faces of the workpiece in a coupled mode. The locking pressure heads are in top connection with the workpiece and used for preventing the workpiece from moving horizontally. The locking pressure heads are arranged in a guiding fixed block in a sliding mode, wherein the guiding fixed block is fixedly installed on the platform top plate. A guide rail slideway is formed in the guiding fixed block and used for establishing moving trajectory of a sphenocephaly connecting plate. The sphenocephaly connecting plate is controlled by a working air cylinder which operates up and down, and the sphenocephaly connecting plate is in linkage with the working air cylinder. A wedge clamping mechanism is formed by the sphenocephaly connecting plate, the guiding fixed block and the locking pressure heads in an assembling mode. The working air cylinder drives the sphenocephaly connecting plate to move up and down. The up-and-down motion of the sphenocephaly connecting plate is converted into the horizontal locking motion of the locking pressure heads by the guiding fixed block. The wedge and pneumatic linkage fixture has the advantages of being high in degree of automation, safe, reliable, convenient to install and clamp and capable of being placed on a machine tool where the workpiece is processed.