The invention discloses a spliced wall brightness uniformity control system comprising light inductors and a circuit control system. The light inductors are correspondingly arranged in all the detection areas of all the display screen backlight boards. The light inductors are used for detecting the actual light perception value of the corresponding detection areas in real time. The light inductors are connected with the circuit control system. The circuit control system is used for acquiring a reference value used for comparing the change of the actual light perception value and acquiring the actual light perception value from the light inductors and comparing the reference value and the actual light perception value. When the absolute value of the difference value of the actual light perception value of a certain detection area and the reference value exceeds the threshold, the circuit control system is used for controlling the driving conditions of the LED lamps on the backlight boards so that the brightness of the detection area is maintained to be uniform to that of other detection areas. The invention also discloses a control method of the spliced wall brightness uniformity control system.