A structure includes a bolt body combined in a toy gun, a bullet feeding element, a high pressure air opening, an air outlet opening, an air valve assembly, a piston element, a recoil bar at one side of the bolt body, a first elastic element fit over the recoil bar, a bolt sleeve defined at one side of the bolt body and movably fit over the recoil bar, and an abutting section. When the high pressure air is input through the high pressure air opening, the air valve assembly may change a flowing direction thereof and drive the abutting section to move so as to control rearward movement of the piston element, the bolt body, and the bullet feeding element. A first elastic element that is operable to move the bolt body forward is disposed on the recoil bar outside the bolt body.