An backlight adjustment circuit (20), configured to adjust luminance of light emitted by one light-emitting diode (LED) string (11) of a LED module (10), the LED string (11) includes a plurality of LEDs (D) and a current control resistor (R). The backlight adjustment circuit (20) includes a light sensing circuit (21) for sensing the luminance of one corresponding LED string (11) and producing a corresponding light sensing signal value; a comparison unit (22) for comparing the light sensing signal value with a preset reference value, and producing a first signal when comparing the light sensing signal value is less than the preset reference value, else producing a second signal; and an adjustment unit (23) for decreasing the luminance of the LED string (11) when receiving the first signal and increasing the luminance of the LED string (11) when receiving the second signal.