Using for function and performance testing of high frame rate detection system, DMD must have the ability to display images with ultrahigh frame rate, but the traditional pulse width modulation (PWM) method can not meet the demand for being limited by the minimum time consumed to load data into DMD. In order to solve this problem, DMD can display images with ultrahigh frame rate. An improved DWM method utilizing the technology that displaying images with background light was proposed, which is based on the combination of hardware features of DMD and traditional PWM theory. This method can be applied to images whose grayscale is not lower than 8bits, and the experimental results show that this method can improve the frame rate of DMD displaying 8bit grayscale images to 1000Hz.