In this paper, an optimized backlight power saving algorithm using joint power-peak signal-to-noise ratio (PSNR) characteristics among multiple frames is proposed. In existing state-of-the-art methods, the optimal decision for clipping point is made only with consideration of current frame, and the target frame PSNR are set the same for all frames. Therefore they have the same power-PSNR performance. In the proposed work, we show that better power-PSNR performance can be achieved by assigning different target frame PSNR for different frames. In the proposed algorithm, the decisions for clipping points associated with all frames are made at once. The inefficiency ratio of each clipping point is evaluated and put into the algorithm design. An optimization problem is formulated, and a solution-search procedure is proposed. Compared with state-of-the-art methods, the proposed work performs better in both aspects of power and PSNR; the BD-PSNR and the BD-Power of the proposed work against all other methods are better for every tested video; the BD-PSNR and the BD-Power can be as high as 19.80 dB on average, and the BD-Power can be as low as -26.25% on average.