The industrial-scale production of Buckminster fullerene (C60) raises concern over its potential ecological and health impacts because of the reported toxicity.To better understand the behavior and effect of C60 in aquatic systems, it is essential to understand its interactions with different environmental factors of natural waters including natural organic matter (NOM).Quantum mechanical calculation can deliver useful information on molecular properties, and explanation on inter-molecular interaction.Interactions of C60 with model Altamaha river humic acid (AR-HA-1) and its similar substance gallic acid (GA) were investigated using classical molecular mechanics,semi-empirical AM 1 and density functional theory (DFT).