Abstract: The design of this system realizes the stack of Ethernet protocol and strives to make it a reality to realize ARP ICMP IP UDP protocol and so on, which shall be able to handle ARP requests, PING(ICMP)orders and UDP communication. Also the system shall be able to write protocols according to the actual needs. The network users can define the protocol and realize the data encryption according to their own needs on condition that a cross twisted pair cable is used to connect the two systems directly. The designing of this system abides by the TCP/IP protocol to realize the information transmission in the network and it can be applied to the distant industrial control, family intelligentization, the cyberization of resources and other fields