A display adjusting system and a display adjusting method thereof are provided. These technical solutions relate to the field of display technology, may reduce power consumption of a portable electronic device, and may improve endurance ability of the portable electronic device. The display adjusting system comprises: a distance measuring module configured to measure a viewing distance, the viewing distance being a vertical distance from a viewing point to a display screen; and a resolution adjusting unit connected with the distance measuring module, the resolution adjusting unit being configured to set a matching resolution based on the measured viewing distance and a resolution power of a human's eye under the measured viewing distance and to adjust a resolution of the display screen to the matching resolution. The display adjusting system may be used to adjust a resolution of a display screen.