Abstract: In order to reveal the effect of organic acid exudation from root on phytoremediation effects, liquid culture experiment was adopted to study the effect of organic acid on physiological characteristics and Pb2+ absorption by ryegrass. It showed that organic acid from ryegrass root were oxalic acid, tartaric acid, malic acid, glacial acetic acid and citric acid. 0.1-1 mmol/L malonic acid and 2-3 mmol/L acetic acid increased the amount of dry matter. 0.1mmol/L tartaric acid, 0.5-1mmol/L malonic acid and 2-3 mmol/L acetic acid could increase the patience index. 1-3 mmol/L malonic acid and tartaric acid could increase the accumulation of Pb2+ in ryegrass shoot. 1-3 mmol/L glacial acetic acid could increase the biomass liveweight of ryegrass and the accumulation of heavy metal Pb2+ in root. The study could provide the certain reference foundation to phytoremediation polluted by heavy metal.