The application of fieldbus has been limited due to the high cost of hardware and the difficulty in interfacing with multivendor products. In order to solve these problems, the computer network technology, especially Ethernet, is being adopted by the industrial automation field. The key technical obstacle for Ethernet for industrial applications is that its nondeterministic behavior makes it inadequate for real-time applications, where the frames containing real-time information, such as control command and alarm signal, have to be delivered within a certain time limit. Recently, the development of switched Ethernet shows a very promising prospect for industrial applications due to the elimination of uncertainties in the network operation that leads to the dramatically improved performance. We propose a trust evaluation model for industrial control ethernet network . Our study shows the importance and necessity of applying theoretical analyses to understand the complex characteristics of trusted industrial control ethernet networks.