A display driving method and device and a display device are disclosed. The method includes: receiving an image signal to be displayed; converting the image signal to be displayed into a virtual pixel array formed by virtual sub-pixels of three colors, and determining the gray scale of each virtual sub-pixel; dividing three successive sub-pixels in a row direction into a pixel unit, and arranging a sampling area at a corresponding position of each pixel unit in the virtual pixel array; and determining the gray scale of the sub-pixel of each color in the pixel unit according to the gray scale of the virtual sub-pixel of each color covered by the sampling area.