Background: The increasing burden of mental health problems continues in the post-COVID-19 era, and nursing interns were particularly likely to experience negative emotions during the pandemic. Both psychological resilience and social support affect negative emotion, but the relationship among the three has not been explored in nursing interns in the postpandemic era. Objectives: To explore the current prevalence of negative emotions among nursing interns and the role of psychological resilience in mediating the relationship between social support and negative emotions in the postpandemic era. Methods: A cross-sectional survey of 788 nursing interns was conducted. The instruments included Psychological Resilience Scale, Social Support Scale, Beck Anxiety Scale and Beck Depression Scale. Structural equation modeling was applied to analyze the mediating role of psychological resilience. Results: The prevalence of anxiety disorder among nursing interns was 24.7%, while that of depression was 10.5%. Pearson correlation analysis showed that both social support and psychological resilience negatively correlated with negative emotions, while psychological resilience positively correlated with social support. Psychological resilience showed a partial mediating effect (53.9%) between social support and negative emotion, with an effect value of -0.1456. Conclusion: Psychological resilience and social support protect nursing students from negative emotions, and psychological resilience partially mediates the relationship between social support and negative emotion in the postpandemic era.