The invention discloses a system for controlling the display gray of a self-closing pulse width modulation panel, which comprises a general controller. A transverse line control circuit and a vertical line control circuit are connected to the general controller. The vertical line control circuit comprises a vertical line opening module, a vertical line closing module and an RS trigger array whichare connected mutually. The output end of the RS trigger array is connected with a vertical line driving circuit, the output end of the transverse line control circuit is connected with a transverse driving circuit, and the vertical line driving circuit and the transverse line driving circuit are both connected with a panel display screen. The method which uses the devices for controlling comprises the following steps: reading data firstly; and then processing data; carrying out valid selection after the RS trigger array is displayed to be opened; and finally displaying the gray. The method and the system for controlling the display gray of a self-closing pulse width modulation panel reduce the use of system hardware resources, especially get a certain advantage in chip area, and can realize gray level control simply and flexibly. The method is also applicable to a space method, a sub-field gray display method and other digital gray control methods.