Abstract: Using field investigations and laboratory experiments, the saline-alkali resistant characters in P. chinampoensis and A. littoralis var. sinensis of alkalization meadow in Songnen Plain were ecophysiologically studied. The results show that both plant species were able to grow in saline, moist and barren soil. The soil in which P. chinampoensis grew was rich in basic salt(Na2CO3) while the soil in which A. littoralis var. sinensis grew was rich in neutral salt (NaC1), indicating their difference in salinealkali resistant characters. The different stress of NaC1 and Na2CO3, content had obvious effects on cell membrane permeability or proline content. The relationship between the stress and cell membrane permeability or proline content could be expressed by logistic curve y = k/( 1 +ea-bx )or straight line y=a+bx. It illustrates that P. chinampoensis was sensitive to the stress due to NaC1. On the contrary, A. littoralis var. sinensis was sensitive to the stress due to Na2CO3. It was true for both species that the ecological adaptation to natural conditions was similar to the physiological adaptation to experimental conditions.