As the development of drive's interface and Blu-ray, the main control system has new requirements. This paper is about the design of the main controller. The data bus and control bus of the drive are separate. The main controller is able to control the drives by sending commands to motor board. The main board receives packets from Ethernet, and converts them to Uart commands of the motor board to control all of the optical disc library. The main controller is at the core of embedded microcontroller S3C2440 based on ARM920T architecture, and transplants embedded Linux which can help to improve development efficiency and portability. It is certified that the main controller meets the requirement in practice.