Addressing nuclear power plant accidents (NPPAs) overwhelms the capability of single jurisdictional government and spans the boundaries of multiple sectors. NPPAs management requires public sectors affiliating to multiple governments, private and non-profit sectors to interact with each other for sharing responsibilities, capabilities and information. How to leverage network to improve collaboration and coordination among all the involved organizations presents challenges for Chinese public administrators in NPPAs management. From the emergency management practice of the earliest nuclear power plants in China, this research investigates and conceptualizes governance mechanisms and associated interorganizational relationships involving in each jurisdictional governmental level and among multiple governments in this specific field. The intergovernmental and cross-sectoral NPPAs management network is built, visualized and analyzed at the levels of the node, link, subset of the nodes and whole network based on Social Network Analysis, and managerial implications of improving inter-organizational collaboration in this field are discussed. Our research shows that the current NPPAs network in China mainly relies on the resources and capabilities of public sectors, and the private and non-profit sectors should be integrated into the network for providing diversified emergency services. NPPAs management network is a hybrid network in the centralized political-administrative structure of China, and hierarchical, market and network governance mechanism play essential roles together and complement with each other in the multi-organizational environment. This network demonstrates the characteristics of selective integration, and the interorganizational relationships that should be paid more attention to be sustained are identified and emphasized from the network perspectives. Furthermore, the absence of collaborative relationships among the organizations that poses barriers to interorganizational collaboration is also discovered and the improvement approaches are discussed. This research provides guidance for improving collaboration in NPPAs management in China, and contributes literatures on emergency management network and interorganizational collaboration in the centralized political-administrative structure.