Circular economy has been recognized as an effective practice of global sustainable development. Eco-industrial park (EIP), as an ideal model for circular economy, attracts increasing concern for its dynamic flow of energy and material, and network nexus of the production-consumption process. Using the circular economy chain of Jiaoyang EIP as an example, combining the methods of material flow, ecological network, and eco-efficiency analysis, this study attempted to determine the network nexus and eco-efficiency of the EIP during 2012-2016. A circular economy chain of the EIP, i.e., the upstream-midstream-downstream chain of industries, was established by material flow analysis. Based on the circular economy chain, especially the byproduct and waste linkages, the ecological network analysis method was adopted to reveal the network nexus characteristics of the Jiaoyang EIP, consisting of the network connectivity, stability, and resilience. The network resilience analysis helped identify the critical nodes that can reflect the cascading effects. Lastly, the eco-efficiency analysis method was employed to examine the circular economy benefits and patterns of the critical node companies. The results from 2012 to 2016 show that:(1) an insufficient network connectivity and stability was supported by a single circular industrial chain in the EIP; (2) the notable cascading effects of the EIP were observed in critical nodes, especially the midstream and downstream companies, which resulted in a less flexible network in the EIP; (3) the insufficient benefits of the circular economy driven by critical node companies implied there was a long way to go toward sustainable pathways for the EIP. Hence, improving strategies of the network nexus and eco-economic synergetic development are proposed for the future circular economy. On the one hand, the awareness of protecting vulnerable companies and controlling cascading failures is emphasized in the optimized network management. On the other hand, the sustainable eco-economic modes of the EIP could be achieved by efficient resource recycling and environmental waste reduction. Our results could provide valuable implications for emerging EIPs and their circular economy exploration within or beyond China.