The invention relates to a double-air-cylinder cover pressing machine. The double-air-cylinder cover pressing machine comprises a pressurizing device, a support used for supporting the pressurizing device, and a height adjusting device used for adjusting the ground clearance of the pressurizing device. The pressurizing device comprises a left side air cylinder and a right side air cylinder which are arranged side by side. The lower end of a piston rod of the left side air cylinder is connected with a semicircular left pressing disc, the lower end of a piston rod of the right side air cylinderis connected with a semicircular right pressing disc, and each of the left side air cylinder and the right side air cylinder is connected with an air pressure difference adjuster. The double air cylinders are utilized for conducting cover pressing on injection molding barrels; and in the press fitting process, air in the injection molding barrels can be exhausted, and accordingly the bulging phenomenon of press-fit barrel covers is avoided.