Abstract: The requirements of connection between numerical control network and office network are given by analyzing the problem of information security in industrial control system. The security risks of numerical control network in military industry are studied, and the solution of information security for is this network proposed. In this solution the functions of security isolation equipment and the terminal security equipment for numerical control system are illustrated. The deployment way of these two equipments are also expressed. The implementation of the scheme would upgrade information security of numerical control network in military industry to insure its information security.

Key words: information security, industrial control system, numerical control network, terminal security, security isolation