【Objective】This study aimed to investigate the effects of aqueous pH and ion strength on dispersity of nano-SiO_2 particles.【Method】The effects of aqueous pH and ion strength on dispersity of nano-SiO_2 with diameter of 10 nm were tested through batch experiments,and the mechanism was proved through multi-ion surface charge-regulation model and Poisson-boltzmann equation analysis.【Result】Dispersity of SiO_2 particles increased with the increase of pH and gradually reached balance after pH 7.39,while it decr...