Objective: To explore the association between greenness surrounding school and aggression among primary school students, and to explore the potential mediating roles of social support, loneliness, particulate matter (PM2.5) and Nitrogen Dioxide (NO2) in this association, in order to provide a scientific reference for preventing and ameliorating aggressive behaviors of primary school students. Methods: The data was used from a survey of children and adolescents conducted in 2015. The Chinese version of the Buss-Warren Aggression Questionnaire was used to assess total and subtypes of aggression, and the mean values of normalized difference vegetation index (NDVI) of 100 m, 500 m, 1 000 m circular buffers surrounding school were used to indicate the participants greenness exposure. PM2.5 and NO2 datas were obtained from the China High Air Pollutants Dataset.Generalized Linear Mixed Models were used to assess the associations of greenness surrounding school with total and subtypes of aggression. Results: Per IQR increment of NDVI-500 m [OR(95%CI)=1.09(1.03-1.15)] and NDVI-1 000 m[OR(95%CI)=1.07(1.02-1.13)] were positively correlated with physical aggression among primary school children, and per IQR increment of NDVI-100 m [OR(95%CI)=0.94(0.90-0.99)], NDVI-500 m [OR(95%CI)=0.93(0.89-0.98)] and NDVI-1 000 m [OR(95%CI)=0.95(0.91-1.00)] were negatively associated with verbal aggression (P<0.05). Mediation analyses revealed that social support partially mediated the association between the NDVI-500 m and physical aggression (mediation ratio:18.0%) and verbal aggression (mediation ratio:-8.3%) among primary school students, and loneliness partially mediated the association between the NDVI-500 m and physical aggression and verbal aggression among elementary school students effects, with proportion mediated ratios of -10.0% and 21.0%, respectively (P<0.05). Conclusions Exposure to school surrounding greenness is likely to associated with physical aggression and verbal aggression in primary school students, and social support and loneliness may partially mediate these associations.