Abstract:Two-year-old seedlings of 16 tree species were grown in pots and treated with salt (NaCl). After 40 days of salinity treatments, the effect of salt stress was studied. The results showed that with the increase of salinity concentration, the contents of proline, soluble sugar and betain increased among all trees. At 400 mmol·L-1 of salt concentration, the proline contents of Elaeagnus angustifolia L. and Ligustrum obtusifolium Sieb. increased by 662.0% and 562.8% respectively compared with that of the control. There was great difference in soluble protein contents among the trees. The Na+ and Cl-contents increased with the increase of salinity concentration in roots, stems and leaves. The Na+ contents in the leaves of Lonicera tatarica L., Rhamnus cathartica L., Cephalanthus occidentalis L. and Buddleja lindleyana Fort. were 5 to 20 times that of the control. The K+ and Ca2+ contents were difference among tree species. Base on the symptom of salt stress and variation characteristics of osmotic adjustment substances it indicates that Tamarix chinensis Lour., Nitraria tangutorum Bobr., Nitraria sibirica Pall., Euonymus alatus (Thunb.)Sieb. and Salix psammophila are high salt-tolerance,. Ligustrum obtusifolium Sieb., Elaeagnus angustifolia L., Celtis laevigata Willd., Gleditsia triacanthos L. and Rhamnus cathartica L. are intermediately salt-tolerance. Pvrus betulaefolia Bunge, Salix(Zhu Liu), Lonicera tatarica L., Buddleja lindleyana Fort., Cephalanthus occidentalis L. and Fraxinus americana L. are moderately salt-tolerance. The changes of proline, soluble sugar and mineral elements (especially Na+, K+, Cl-) on the salt tolerance of plants are more common and greater.