To reduce the energy consumption of LED backlight LCD, the four-primary-color backlight schemes are proposed. The energy-saving performance and chromatic aberration of the four-primary-color LED reproducing colors are studied. Firstly, since the human eye is not sensitive to red light, a method to use the fourth primary color instead of red is proposed to represent the color. To achieve the best energy-saving effect, the radiate luminous efficiency is introduced to determine the fourth primary color. Next, the method of converting the three primary colors to the four primary colors is explained by means of color gamut partitioning. Finally, how to evaluate the chromatic aberration of the reproduced colors is introduced. The results show that by using OGB colors instead of the popular RGB colors to reproduce composite colors, the average power consumption is reduced by more than 20%, and the average chromatic aberration of the reproduced colors of OGB and RGB is less than 1.5. This paper proposes a four-primary color LED backlight scheme, which has a good energy-saving effect for LCD and meets the requirements of current display accuracy and energy saving.