Studies show green space is associated with lower prostate cancer incidence, but its effect on survival outcomes remains unclear. This study aims to assess whether green space improves prostate cancer survival outcomes. We examined the associations of green space with mortality in men with prostate cancer diagnosis. We conducted a retrospective cohort study using data from the Surveillance, Epidemiology, and End Results (SEER) database (1995-2019), covering 12.24 % of the U.S. population. Green space exposure was measured using annual averaged Normalized Difference Vegetation Index (NDVI). Associations between NDVI and mortality were evaluated using cause-specific Cox regression models, adjusting for demographic, clinical, socioeconomic, environmental, climate, and social capital factors. Effect modifications by race/ethnicity and surgery status were also examined. In this multi-state population-based study in the US, we found that long-term exposure to green spaces was associated with lower risks of prostate cancer specific mortality (3-5 years, HR = 0·74, 95 %CI [0.69-0.79]). NDVI has effect modification on race, with NDVI showing the strongest protective effect in Non-Hispanic Whites and Non-Hispanic Blacks. Higher NDVI reduced the negative impact of not undergoing surgery on prostate cancer-specific mortality (low NDVI: HR = 1.98, 95 % CI [1.87-2.11]; high NDVI: HR = 1.70, 95 % CI [1.59-1.82]). These findings emphasize the importance of creating better living environments for advanced-stage patients, highlighting the potential value of integrating green spaces in hospice and palliative care settings to enhance end-of-life care.Copyright © 2025. Published by Elsevier Ltd.