A solution culture experiment was performed to investigate the impact of phenanthrene (PHE) on organic acids secretion and accumulation by Lolium perenne L. root. Data showed that, oxalic acid was the dominant composition of organic acids in root and root exudates. In root exudates, increased levels of PHE resulted in higher oxalic acid and its secrete proportion; oxalic acid arranged from 3.00 to 4.72 mg/g FW under spiked PHE treatments, in control, it was 2.33 mg/g FW. In root, oxalic acid rose to 25.61 mg/g FW at 1 mg/L PHE treatment, while the PHE concentration was continuously increasing, organic acids in root decreased.