Disclosed are a method and device for controlling low grayscale white balance. The method comprises: calculating a total color difference ΔE(nmax−0) between a grayscale 0 and a grayscale threshold value nmax, according to measured tristimulus values of the grayscale 0 and the grayscale threshold value nmax; determining a color difference relation between various grayscales from the grayscale 0 to the grayscale threshold value nmax, according to the total color difference ΔE(nmax−0) between the grayscale 0 and the grayscale threshold value nmax, wherein the color difference relation enables human eyes to observe a gradual and smooth change from the grayscale 0 to the grayscale threshold value nmax; and controlling white balance according to the color difference relation between various grayscales from the grayscale 0 to the grayscale threshold value nmax. By means of the method, the present invention can automatically adjust white balance, and the transition between low grayscales can be smooth and natural when observed by human eyes.