The invention relates to the technical field of display, in particular to a power-saving and image distortion-free CABC method, comprising the following steps: step A, enabling a CABC chip; B, according to the requirement of the energy-saving degree, setting N different energy-saving grades for the CABC in sections, N >= 3; C, controlling nodes of that GAMMA curve, divide the GAMMA curve into a plurality of different segments according to each different energy-saving grade set in the step B; Step D, after setting different energy-saving grades corresponding to different segments of the GAMMA curve, determining the GAMMA value and the change value of the PWM to adjust the backlight brightness, and when the PWM value is adjusted to reduce the backlight brightness by K%, increasing the corresponding GAMMA value by K% and K% <= 50%. The power saving and image distortion-free CABC method realizes the same effect of the GAMMA curve as that before the CABC function is not turned on, and brings longer endurance time to a plurality of LCD screen handsets.