The invention discloses a backlight control method based on LED drive. The backlight control method based on LED drive includes the steps: acquiring the gray-scale value corresponding to each subareain an image; calculating the mean value, that is, the gray-scale mean value, of the gray-scale values of all the subareas in the overall image; according to the gray-scale value corresponding to eachsubarea and the gray-scale mean value, determining the current value and the pulse width modulation duty ratio of the LED array corresponding to each subarea; and according to the determined current value and pulse width modulation duty ratio, driving the LED array corresponding to each subarea so as to adjust the backlight brightness value of the LED array corresponding to each subarea in real time. The invention also discloses a backlight control system based on LED drive. The backlight control method and system based on LED drive can realize dynamic change of the brightness required by backlight of the current high-dynamic range graph on the basis of the current partially dimming backlight hardware, do not increase the power supply circuit cost and the design complexity, and can guarantee the detailed display effect of the image.