Abstract:A soil-cultivating test, with rhizobag technique, was conducted to quantify the eco-physiological responses of maize seedlings (Zea Mays L.) in terms of soluble sugars, common low molecular weight organic acids and amino-acids in root exudates under three concentration levels of pyrene (50, 200, and 800 mg kg-1, denoted by T1, T2, and T3, respectively). Maize growth was positively stimulated under the lowest pyrene concentration, while inhibited in the higher pyrene concentrations, and the inhabitation effect on maize growth increased with increasing pyrene concentration in soil. The effect on roots was higher than that on shoots. The contents of soluble sugars, common low molecular weight organic acids and amino-acids in root exudates were promoted with pyrene treatments. The contents of soluble sugars in root exudates of maize seedlings in T1, T2, T3 treatments were respectively 1.14, 1.81, 1.35 times than those in control treatment, 1.24, 4.31, 2.94 times for common low molecular weight organic acids, and 1.58, 5.56, 5.40 times for amino-acids. The contents of acetic acid were in decreasing order of T2>T3>T1, tartaric and citric were T3>T2>T1, oxalic were T3≈T2>T1. The pyrene addition did not affect types of amino acids, but significantly affect the contents of each amino-acid. Under different concentration of pyrene, the contents of asparagic, serine and alanine were T3>T2>T1, while threonine, glutamic acid, proline, glycine, ctstine, valine, methionine, isoleucine, leucine, tyrosine, phenylalanine, lysine, γ-amino-butyrioacid and ornithine were T2>T3>T1.