Due to the complicity of the water network,the systematic analysis of water use/drainage and structure of the water network is fundamental for integrated system optimizations.In this paper, the water network system of a typical coal-to-olefins project was selected as a case study to analyse the structure and water use efficiency of the water network system based on the ecological network analysis method. Specifically, the network flux analysis and utility analysis were employed for the structure analysis of the selected water network. Results of flux analysis showed that the first cooling water station had the largest proportion of 35.70%, followed by the second cooling water station with a proportion of 26.35%. For the utility analysis, the networkmutualism index (M) was adapted as the measure of the network structural stability. For the case study, the M value was obtained as 0.97, which was very close to one. From the perspective of ecology, the strength of competition and symbiosis was approximately equivalent, indicating strong collaboration among nodes in this network.