An image adjusting method applied to a display with an ambient light sensor, the image adjusting method comprising: utilizing the ambient light sensor to detect surrounding illumination of the display; determining to which one of a plurality of brightness domains the detected surrounding illuminance conforms and adjusting the backlight brightness as a value corresponding to the conformed brightness domain; wherein if the backlight brightness has been increased according to the value corresponding to the conformed brightness domain decreasing intensity of high gray-scale pixels via a first amending function (Ca1, Cb1, Ca1', Cb1', C1, C1') and adjusting intensity of other pixels excluding the foresaid pixels having the specific gray-scale values on the display via a second amending function (Ca2, Ca2', C2); and if the backlight brightness has been decreased according to the value corresponding to the conformed brightness domain, increasing intensity of low gray-scale pixels; via a first amending function (Ca1, Cb1, Ca1', Cb1', C1, C1') and adjusting intensity of other pixels excluding the foresaid pixels having the specific gray-scale values on the display via a second amending function (Ca2, Ca2', C2); wherein the first amending function (Ca1, Cb1, Ca1', Cb1', C1, C1') is varied according to the conformed brightness domain and wherein the pixels with the specific gray-scale values are high gray-scale value pixels or low gray-scale value pixels; and the second amending function (Ca2, Ca2', C2) is not varied according to the conformed brightness domain; wherein the first amending functions are predetermined functions respectively corresponding to the plurality of brightness domains. utilizing the ambient light sensor to detect surrounding illumination of the display; determining to which one of a plurality of brightness domains the detected surrounding illuminance conforms and adjusting the backlight brightness as a value corresponding to the conformed brightness domain; wherein if the backlight brightness has been increased according to the value corresponding to the conformed brightness domain decreasing intensity of high gray-scale pixels via a first amending function (Ca1, Cb1, Ca1', Cb1', C1, C1') and adjusting intensity of other pixels excluding the foresaid pixels having the specific gray-scale values on the display via a second amending function (Ca2, Ca2', C2); and if the backlight brightness has been decreased according to the value corresponding to the conformed brightness domain, increasing intensity of low gray-scale pixels; via a first amending function (Ca1, Cb1, Ca1', Cb1', C1, C1') and adjusting intensity of other pixels excluding the foresaid pixels having the specific gray-scale values on the display via a second amending function (Ca2, Ca2', C2); wherein the first amending function (Ca1, Cb1, Ca1', Cb1', C1, C1') is varied according to the conformed brightness domain and wherein the pixels with the specific gray-scale values are high gray-scale value pixels or low gray-scale value pixels; and the second amending function (Ca2, Ca2', C2) is not varied according to the conformed brightness domain; wherein the first amending functions are predetermined functions respectively corresponding to the plurality of brightness domains.