Disclosed is a spliced display device and a backlight control method therefor. The spliced display device includes a plurality of display modules that include respective backlight modules. Each of the backlight modules includes a plurality of backlight partitions, of which a first backlight partition is located at edge of a corresponding backlight module of the backlight modules. The backlight control method comprises the steps of obtaining an initial brightness value and a reference brightness value for the first backlight partition, adjusting the initial brightness value of the first backlight partition according to the reference brightness value to obtain an adjusted brightness value for the first backlight partition, and controlling the brightness of the first backlight partition according to the adjusted brightness value.