Abstract: Exposed to high concentrations of Na2SO4(1% and 2%),the permeability of plasma membrane and membrane-lipid peoxidation of Seriphidium schrenkianum, Artemisia ratifolia, Festuca arundinacea and Dactylis glomerata were increased. But the increases in the permeability of plasma membrane and the membrane-lipid peroxidation were more prominent in salt-resistant species, Seriphidium schrenkianum and Festuca arundinacea, than the salt-sensitive species, Artemisia ratifolia and Dactylis glomerata. The activities of the superoxide dismutase (SOD) and catalase (CAT) in the graminaceous family (F. arundinacea and D. glomerata) increased with increasing concentration of Na2SO4, while those in the composite family (S. schrenkianum and A. ratifolia) decreased. In the graminaceous family, the rate of increase of SOD and CAT activities in the salt-resistant grass (F. arundinacea)was higher than that in the salt-sensitive grass (D. glomerata),while in the composite family, the rate of decrease of SOD and CAT activities was lower in the salt-resistant grass (S. schrenkianum) than that in the salt-sensitive species (A. ratifolia). Within the same family, the relative contents of carotene in the salt-resistant grasses were higher than those in the salt-sensitive grasses.