Backgrounds: Nursing is the key group to provide healthcare services, and it is easy for nursing staff to develop mental health problems. Aims: The study aimed to evaluate prevalence of psychological symptoms in nurses working in an intensive care unit (ICU) and the inter-relationship of associations of psychological symptoms using network analysis. Methods: This study is a cross-sectional design study. The Chinese version of the Symptom Check List-90 (SCL-90) was used to measure the psychological status of ICU nurses. The network structure of psychological symptoms was characterised, and indices of ‘Expected influence’ were used to identify symptoms central to the network. Network stability was examined using a case-dropping bootstrap procedure. Results: Multiple logistic regression analysis found those who had worked more than 15 years were less likely to experience positive psychological symptoms, whereas nurses working in emergency ICU and other ICUs, nurses working in departments with over 16 beds were more likely to develop psychological symptoms. In addition, ‘Anxiety’, ‘Mental degeneration’ and ‘Depression’ were central symptoms in the network. Conclusions: ICU nurses reported a high level of psychological symptoms, which may affect the quality of their work and worsen public health problems.