The study developed a predictive model of secondary traumatic stress (STS) in emergency department nurses based on data from 186 nurses from a single hospital. The Vicarious Traumatization Questionnaire (VTQ), the Chinese version of the Interpersonal Reactivity Index (IRI-C), the Perceived Stress Scale (PSS) and the Connor-Davidson Resilience Scale (CD-RISC) were used. The results showed a significant association between STS, job stress, empathy, and psychological resilience, with higher stress and empathy, along with lower resilience, being correlated with higher STS. Subfactors such as personal fear, emotional resonance, and exposure to traumatic events had the strongest associations. The regression model explained 56.00% of the variance in STS scores. Psychological resilience acts as a protective factor and the model has clinical utility for interventions to improve nurses' mental health and quality of care. The findings highlight the need for targeted psychological support strategies in the emergency department setting.