A display device includes a display, a driver, a memory, and a controller. The display includes a display panel and a backlight unit with a plurality of light-emitting elements to display an image. The driver is electrically connected to the display to transmit a backlight control signal to the backlight unit. The memory stores a plurality of adjustment instructions, and each adjustment instruction includes a drive frequency and a control parameter. The controller is electrically connected to the display, the driver, and the memory. The controller is configured to determine a drive frequency and a control parameter corresponding to the drive frequency in the memory according to a frequency adjustment signal, and then adjust the backlight control signal according to the control parameter, to change a duty cycle of the backlight control signal, so that a refresh rate of the backlight unit meets a requirement of a user.