The invention relates to a pulse controlling system for air bag polishing, which comprises an air bag polishing mechanism, an air source and a driver, wherein the air bag polishing mechanism comprises an air containing cavity, a rubber air bag and a holding rack. The holding rack is linked with a direct current motor. The rubber air bag is provided with a pressure sensor for detecting the actual pressure in the air bag. The driver comprises a first electromagnetic valve, a second electromagnetic valve and a timer, wherein the first electromagnetic valve is used for communicating the air source and the air containing cavity; the second electromagnetic valve is used for communicating the air containing cavity and the air; the timer for the first electromagnetic valve and the second electromagnetic valve is controlled by the controller to generate control square waves to control the two electromagnetic valves to be opened and closed. The air source is connected with a 2D valve. The area of the valve opening of the 2D valve presents the periodic change, and then the air charging pressure in the rubber air bag presents the period change. The 2D valve is connected with the air containing cavity, and is controlled by a central processing unit. The pressure signal sensed by a pressure sensor is transmitted to the central processing unit. The invention has the advantages of quick improvement of surface quality of the module, and short polishing time.