Base on the analysis of the information and the functional requirement, a framework of the petrochemical tank farm supervision system and the key method of the monitoring software are put forward which included the technology of the PLC control net and the industrial configuration software-Citect. The application shows that this system runs reliable,and the HMI is friendly and is easy to operation, in other words, the system is a full functioning system and can be used in the similar petrochemical terminal.