Abstract: Integrating all the water-consumption processes and the whole production process of an iron and steel complex into a water-consumption network system, then the model of the system was developed with its evaluation index system given via the following-observing model of SFA (substance flow analysis). An iron and steel complex in China was taken as an example to which a water-consumption network model was developed to find out the problems in water-consumption system, thus analyzing its optimization and evaluation. The results revealed that the system has even more water-saving potential in such processes as coking, continuous casting and rolling with a high potentiality of water-environment efficiency as an evaluation index and remarkable water-saving achievement due to optimization. All of these showed that the SFA following-observing model is available to theoretically optimize the water-consumption network in an iron and steel complex.