Extensive research has demonstrated the benefi cial eff ects of natural environments on the emotional well-being of older adults. However, the relative signifi cance and specifi c contributions of individual background characteristics, the intensity of sensory engagement, duration of exposure, and environmental features during nature experiences remain inadequately understood. This study develops a multidimensional analytical framework to assess the emotional responses of older adults, based on in-situ data collected from individuals with diverse backgrounds during real-life nature engagements. By integrating the Random Forest and SHAP (SHapley Additive exPlanations) analytical methods, the study quantitatively assesses the relative signifi cance and infl uence patterns of individual background, sensory engagement intensity, exposure duration, and audiovisual environmental characteristics on emotional modifi cations subsequent to nature exposure. The results indicate the following: (1) Audiovisual environmental characteristics, the degree of sensory engagement, and exposure duration exert a greater infl uence on emotional outcomes than individual background factors. Sensory engagement, in particular, plays a crucial role in fostering positive emotions, suggesting that the way nature is experienced may be more signifi cant than attributes of nature itself. (2) Age and educational attainment exhibit a negative correlation with emotional improvement, whereas spending more than 10 hours per week in nature correlates positively with emotional well-being. (3) High-intensity visual and olfactory experiences signifi cantly enhance positive emotions. The optimal duration for a single nature engagement is between 31 and 60 minutes; exceeding this range, the benefi cial eff ects tend to diminish. (4) Audiovisual environmental features demonstrate threshold eff ects on emotional responses among older adults. These fi ndings off er practical insights for the design of nature-based interventions that support emotional well-being in older populations and provide scientifi c evidence to inform the planning and management of age-friendly parks and outdoor environments.