In recent years, with the improvement of consumers' pursuit of display quality, in the field of LCD display, the direct‐light backlight technology is increasingly used in TV, MNT, NB, VR, Pad and even automotive display fields. Using this technology to zone the backlight can achieve local dimming technology, that is, adjust the brightness of the single backlight zone according to the image. Thus, high contrast ratio and high color gamut can be achieved while reducing power consumption. However, compared with the traditional edge‐light display, the halo effect of the direct‐light backlight display greatly affects the visual effect. At present, backlight design tends to be highly zoned, which will affect the halo effect and contrast ratio. And as customers pursue further improvement in optical property, the 3D reflector design to enhance the luminance of the single zone will also affect contrast ratio and halo effect. In this paper, we explored the influence of zone size and 3D reflector design on halo effect and contrast ratio, so as to guide the subsequent products to carry out appropriate zone size design.