An automatic regulator of LED backlight optical parameters based on ambient light detection comprises an I2C interface, an illumination calculating module, a luminance comparator, a luminance value register, a data sending module and a luminance value regulating module. The I2C interface is connected with the illumination calculating module; the illumination calculating module is connected with the luminance comparator; the luminance comparator and the luminance value register are used for comparing the luminance value of ambient light with a backlight luminance value of the last condition and stored in a current luminance value register; the luminance value register is connected with the data sending module; the data sending module is connected with the luminance comparator and the luminance value regulating module; the luminance value regulating module is connected with the luminance comparator. In order to make full use of the advantages of an LED backlight television in the aspects of picture quality and an energy-saving lamp, the parameter regulation can be conducted on the automobile regulator according to the visual effect of the eyes of a person and the automobile regulator can protect the vision of a watcher and can release visual fatigue of the watcher.