Abstract: Ethernet has been applied in the Intranet after its real-time technology was improved. It is yet the major obstacle that the Ethernet is not a real-time communication technology when the Ethernet is tried to be used in the infranet. In this paper, several real-time communication technologies of industrial Ethernet were discussed, then the solution of Ethernet Powerlink belonged to deterministic industrial Ethernet was introduced. Ethernet Powerlink can work in the infranet.