A method of controlling the brightness of a backlight in a terminal, comprising: acquiring an image currently displayed on a screen of the terminal and determining a grayscale of each of a plurality of pixel points of the image; from the grayscales of the plurality of pixel points of the currently displayed image, determining for each grayscale the number of pixel points having said grayscale; acquiring N grayscales, the N grayscales being those with the first N largest numbers of pixel points, where N is a preset positive integer; determining a difference between each two grayscales from the N grayscales, comparing each of the determined differences to a first preset value; determining the ratio of the sum of the numbers corresponding to the N grayscales to a sum of the numbers of all the grayscales, and comparing said ratio to a second preset value; when each difference between the N grayscales exceeds the first preset value, and the ratio of the sum of the numbers of the N grayscales to a sum of the numbers of all the grayscales exceeds the second preset value, the method further comprising the steps of determining a brightness adjustment parameter corresponding to the image; and reducing a current brightness of the backlight based on the determined brightness adjustment parameter; wherein the determining the brightness adjustment parameter corresponding to the image comprises: determining a contrast of the image; and determining a brightness adjustment parameter corresponding to a contrast range to which the contrast of the image belongs according to a pre-stored corresponding relationship between the contrast range and the brightness adjustment parameter; wherein the brightness adjustment parameter is such that a reduced amount of the backlight brightness is relatively large when the contrast of the image is high and is relatively small or unchanged when the contrast of the image is low. acquiring an image currently displayed on a screen of the terminal and determining a grayscale of each of a plurality of pixel points of the image; from the grayscales of the plurality of pixel points of the currently displayed image, determining for each grayscale the number of pixel points having said grayscale; acquiring N grayscales, the N grayscales being those with the first N largest numbers of pixel points, where N is a preset positive integer; determining a difference between each two grayscales from the N grayscales, comparing each of the determined differences to a first preset value; determining the ratio of the sum of the numbers corresponding to the N grayscales to a sum of the numbers of all the grayscales, and comparing said ratio to a second preset value; when each difference between the N grayscales exceeds the first preset value, and the ratio of the sum of the numbers of the N grayscales to a sum of the numbers of all the grayscales exceeds the second preset value, the method further comprising the steps of determining a brightness adjustment parameter corresponding to the image; and reducing a current brightness of the backlight based on the determined brightness adjustment parameter; determining a brightness adjustment parameter corresponding to the image; and reducing a current brightness of the backlight based on the determined brightness adjustment parameter; wherein the determining the brightness adjustment parameter corresponding to the image comprises: determining a contrast of the image; and determining a brightness adjustment parameter corresponding to a contrast range to which the contrast of the image belongs according to a pre-stored corresponding relationship between the contrast range and the brightness adjustment parameter; wherein determining a contrast of the image; and determining a brightness adjustment parameter corresponding to a contrast range to which the contrast of the image belongs according to a pre-stored corresponding relationship between the contrast range and the brightness adjustment parameter; wherein the brightness adjustment parameter is such that a reduced amount of the backlight brightness is relatively large when the contrast of the image is high and is relatively small or unchanged when the contrast of the image is low.