To resolve the issue of manual dimming for lightplate lighting system in civil aircraft cockpit that increase pilot’s work loading, and not easily to precisely control the brightness of lightplate according to cockpit luminous environment, digital self-adjusting dimming control system of lightplate has been proposed. The background luminance is accurately measured with ambient light sensors, and based on luminance curve model, each lightplate illumination is computed, to realize self-adjusting of lightplate luminance combined with manual compensation and PWM dimming control technology, self-adjusting dimming effects of lightplate brightness is realized finally. Based on above solution, the design of system architecture and scheme design of main system components are completed. By simulation，prove that self-adjusting dimming control system can realize the expected objective. It can adjust the luminance of the lightplates exactly, and provide an effective way to improve the human ergonomics of aircraft lightplate lighting system.