A display device and a display driving method thereof are disclosed. The method includes: acquiring a grayscale of each pixel in a pixel matrix of a to-be-output image of the display device, wherein the pixel matrix comprises a plurality of pixels in a plurality of pixel rows, and each pixel row comprises multiple pixels; determining a refresh type and a refresh rate for the to-be-output image according to the grayscale of each pixel in the pixel matrix, wherein the refresh type comprises a single-frequency refresh and a multi-frequency refresh; and refreshing pixel voltages of the pixel matrix at a single determined refresh rate under the single-frequency refresh, or refreshing the pixel voltages of the pixel matrix at a plurality of determined refresh rates under the multi-frequency refresh.