Abstract: Phragmites australis has a strong capacity of the absorption to heavy metal cadmium, which can effectively reduce the cadmium content of its growing environment. After being abstracted by reed, the cadmium is converted into different forms. The cadmium extracted by sodium chloride (SCd) is the main form in reed. In order to study the effects of different concentrations of cadmium on the SCd and the activity of gamma-glutamylcysteine synthetase (γ-GCS) in reed, the cadmium chloride solutions of 5 levels (0.5, 1.0, 2.0, 3.0 and 5.0 mmol·L^-1) were used to irrigate the Phragmites australis at different growth stages, and the accumulation of cadmium (SCd) and the change activity of γ-GCS in reed were measured. The results show that:(1) When the concentration of cadmium chloride solution increased, the accumulation amount of SCd in the roots, stems, and leaves of reed first increased and then decreased; (2) The accumulation amount of SCd in different parts of the reed was different at different stages. During the mature stage, the accumulation amount of SCd reached the maximum. It was 3 984.16 mg·kg^-1 in root, which was 7.33 times as that in the stems, and 4.83 times as that in leaves; (3) When the concentration of cadmium chloride solution was less than 3.0 mmol·L^-1, the activity of γ-GCS in roots, stems and leaves of reeds increased with the increase of concentration of cadmium chloride solution. When the concentration of cadmium chloride solution was greater than 3.0 mmol·L^-1, the activity of γ-GCS was suppressed.