Abstract: Electrowetting electronic paper (EWD) has the characteristics of low power consumption, wide angle of view, fast response speed and so on. However, the gray scale display reflectivity is low and display instability, so an improved scheme is proposed to display gray-scale in EWDs based on a waveform design method which includes pulse width and amplitude modulation. Firstly, the design of the driving waveform based on pulse width and amplitude modulation, and char breakup refresh mode is used to scan the EWD. Secondly, the screen opening rate is test at each voltage value point, and the electrowetting hysteresis curve is obtained at the same time, then, the gray scale is divided according to weber law combined with hysteresis curve. Experimental results show that a clear 8 level gray scale EWD system with a maximum reflectivity of 70% can be achieved by the proposed driving scheme.