A networked control system is developed for a rolling shear line in this paper. In order to ensure the real time and reliability of communication, the PROFIBUS-DP is employed to structure a networked control system. Automatic cutting to length of steel plate is realized by that control system. The system has been running well since put to use, and the production efficiency is improved. Using the networked control system, not only it is easy to install and reconfigure, but also the costs of the setup and maintenance are reduced. The performance of the networked control system can satisfy the requirement of the rolling shear line.