We have studied the dynamic changes of the ethylene release, the polyamine concentrations, the reactive oxygen accumulation, and the permeability of plasma membrane in Peganum multisectum leaves under drought stress using pot culture experiment. The concentration of malondialdehyde (MDA) and the permeability of plasma membrane in P. multisectum leaves increase with the increase of the drought stress and the length of stress time. Under light drought, the rate of ethylene production, the concentration of putrescine (Put), spermine (Spm), spermidine (Spd), O-•2, H2O2 and MDA, as well as the activity of polyamine oxidase (PAO) have no significant changes with the increase of the length of stress time. At the early stage (0-30 days) of moderate and heavy drought, the concentration of Put, Spm, and Spd increases abruptly, the rate of ethylene production decreases, and the concentration of O-•2, H2O2, and MDA and PAO activity in P. multisectum leaves keep almost unchanged. While at 45-75 days, on the contrary, the concentration of Put, Spm and Spd decreases, and the concentration of O-•2, H2O2,and MDA increases substantially. The permeability of plasma membrane and the rate of ethylene production also increase. The release of ethylene has strong correlation with the concentration of O-•2and H2O2 in P. multisectum leaves. It indicates that under moderate and heavy drought, the production of ethylene and polyamine constrains each other in P. multisectum leaves, the accumulation of O-•2, H2O2 induced by the increase of ethylene release results in the abrupt increase of the permeability of plasma membrane.