In order to improve the effect of night vision compatible liquid crystal display (LCD), infrared LED is used on top of the RGB three-color LED as the backlight source, and different LEDs are arranged to form two sets of light sources at different modes. According to the brightness and uniformity requirements of the 10.4 in (1 in=2.54 cm) backlight source, backlight is used as a Lambert luminous body to select the type of LED by calculation, to determine the number and arrangement of LED, to select the optical films reasonably, and to design the structure of the backlight module. Because the luminous power of infrared LED is adjustable, in night vision compatible mode, the information can be seen on the LCD screen not only through night vision device but also with naked eyes. Simulation and analysis by TracePro software show that the designed backlight module meets the two requirements of the LCD screen of visible features under the bright light and night vision compatibility.