The invention discloses a high-speed air cylinder. The high-speed air cylinder comprises an air chamber and a guide cylinder, wherein the air chamber and the guide cylinder are assembled into a cylinder body, an air inlet end of the guide cylinder is inserted into the air chamber from the side face of the air chamber and forms a sealing and fixing structure with the air chamber, the sealing and fixing structure is the same as a first air inlet pipeline and a second air inlet pipeline, air is directly conveyed to the guide cylinder and the air chamber, a one-way valve and an air inlet valve areinstalled on the first air inlet pipeline, the one-way valve is located between the air outdoor wall and the air inlet valve, and an air inlet valve is arranged on the second air inlet pipeline; a piston rod is arranged in the guide cylinder, and a gap is formed between the piston rod and the guide cylinder; and an air gap is formed in a part, located in the air chamber, of the guide cylinder, and sealing parts are arranged on the inner walls of the guide cylinders at the two ends of a ventilation gap respectively, so that when the piston rod is located in the position of the ventilation gap,an airtight seal is formed among the air chamber, the guide cylinder and the piston rod. The device can effectively achieve high-speed movement of the piston rod.