Abstract: The security of the industrial control system is related to the national economy and people’s livelihood， and is an important part of national security. With the continuous development of the Internet of Things technology， the industrial control system network has penetrated into various industries. However， due to design defects or lack of security means， the relevant assets of the industrial control system are extremely vulnerable to hackers and exploits. Detecting and knowing the industrial control assets exposed to the Internet environment is an important step to realize the information monitoring of the industrial control system， find security loopholes and grasp the security situation of cyberspace. This paper introduces the commonly used detection methods for industrial control system network asset detection. The port detection technology is used to scan the ports on the target host， and then the industrial control protocol and general protocol network asset detection technology is used to discover industrial control equipment and collect asset information according to the port opening. Through the Internet experiment， the data of the detection results are comprehensively analyzed， the characteristics of the network asset detection technology of the industrial control system are summarized， the problems existing in the current technology are pointed out， and the future development is prospected.

Key words: industrial control system, network asset detection, asset fingerprint, protocol detection