Aim Emergency department nurses experience varying degrees of mental workload due to various reasons. The group with medium to high levels of mental workload needs to be given attention. There is limited research on the potential profiles of mental workload among emergency department nurses. The purpose of this study is to identify different potential profiles of mental workload among emergency department nurses and analyze influencing factors.Design: A cross-sectional study.Methods This study follows the STROBE guidelines. This study used the NASA-TLX scale to assess the mental workload of emergency department nurses and employed latent profile analysis to identify different potential profile of their mental workload. Statistical methods Pearson chi-square and logistic regression analyses were performed to identify factors affecting the mental workload of emergency department nurses.Results A total of 305 emergency department nurses completed the survey, with the majority experiencing moderate to severe mental workload. mental workload is influenced by multiple factors and is a complex and dynamic process. The main factors that affect mental workload included age(year), marital status, monthly income(RMB), support style, coping style, and personality traits.Conclusion The results of this study suggested that mental workload experienced by emergency department nurses was widespread. We should pay attention to the mental needs of emergency department nurses and pay attention to their mental health status.