At present the electronic instrument almost takes serial port as the communication interface, it cannot accessing into the network, the design of an embedded serial server module is proposed. The module employs embedded chip S3C2440A as the microprocessor, takes Ethernet controller chip RTL8019AS, level conversion chip MAX3232 to convert the data, and transplants Light-weight IP Stack protocol into uC/OS-II operating system. Transparent data transmission realized between serial port and Ethernet. The experiment shows that this device runs stably and meets the need of communication in industrial environment.