In the factory network environment, analyzing the packets heard is like language analysis. The communication between the machines in the factory is like the communication between the Boss and the Servant. The communication language may be Chinese, English, Japanese, but it may also be an unknown dialect (Unknown Protocol). Therefore, after hearing the packets of the industrial control network environment, how to find and "see" unknown protocols, and automatically analyze the unknown industrial control protocols to increase the accuracy of IDS and reduce misjudgment is an important issue.