EtherNet/IP protocol (EIP) is a new standard of field bus standard. It is an open industrial networking standard that supports real-time I/O messaging, explicit message exchange. This paper has a discussion on the structure of EIP, EIP packet encapsulation and its application in industrial area. And it analyses the working principle of CIP, which includes objects, services, and application data. In addition, it studies how EIP realize Explicit Messaging and Explicit Message. It gives the analysis of application of EIP in industrial area.