Abstract: In 1987 and 1989, study and analysis on the salt-harmed Populus euphratica Oliv. had been conducted by using one to two years old stocks, under the condition of water-culture with the salt concentration controlled by a conductivity meter. The results show that the order of harmful salt on stocks are Na2CO3NaHCO3NaClCaSO4MgSO4salinized soil covers composed of NaCl mainly; CaSO4 did no harm to the stocks. The symptoms were clearer on one years old stocks than those on two years old stocks when they were harmed by salts, but the general trends were the same. When salts were added into distilled water, the solutions killed the stocks, which grew new roots in distilled water, were 0.05% Na2CO3, 0.07% NaHCO3, 0.17% NaCl, 0.7% CaSO4,1.9% MgSO4 and 3.5% salinized soil covers composed of NaCl mainly. When salts were added into the salt water, the salt-resistance index of stocks which grew new roots in salt water could be raised to 1.1% NaCl, 3.5% MgSO4 and 3.7% salinized soil covers composed of NaCl mainly. It shows that the salt-resistance ability of the stocks can be raised significantly after they are treated by salt-resistance treatment.