| The paper studied on ecological and physiological indications variation of six common plants under different water stress with a pot method. The ecological indications included plant height, diameter, biomass and water consumption, which could show plant growth condition, plant completions and plant water use efficiency change; The physiological indications included variation of leaf water potential, PV curves of different plants, chlorophyll content, Membrane permeability, MDA content, Proline content and enzyme activity of antioxidant system, which could show the way to adapt water stress in physiological direction. The results mainly as follow:(1) The results of plants biomass showed that the competitiveness of Grass bothriochloa, Lespedeza davurica and Setaria was relatively high, and the other three plants were lower, in which Lespedeza davurica was the highest and the artemisia gmelinii was the lowest.(2) Water saturation deficit (WSD) and the the osmotic potential of plasmolysis point fitted by PV curve was significantly correlated. This two indexes could be to determine plants drought-resistance characteristic, six plants drought-resistance capocity in order was Lespedeza davurica>Grass bothriochloa>Giraldii>Setaria>Artemisia gmelinii>Artemisia scoparia.(3) The results of physiological indicators of drought-tolerant plants showed that Chlorophyll content decreased, rate of Chlorophyll a and b,Chlorophyll decreased, Membrane permeability increased, MDA content increased, Pro content and antioxidant-protective enzymes activity changed as water stress degrees increase and water stress time extension. The appearance of six plants was similar as hurt by drought stress, but the regulation and adaptation methods were different. The decrease and increase of six indexes under low water treatment was different from under high water treatment, and Chlorophyll content, rate of Chlorophyll a and b, Membrane permeability, MDA content, Pro content, SOD activity,POD activity and CAT activity of six plants species as follow:Artemisia scoparia (decreased by 54.84%, increased by 1.17%, decreased by 23.86%, increased by 4.42%, increased by 75.99%, increased by 15.17%, decreased by 19.21%, decreased by22.31%), and the main material to resistant drought was Pro and SOD. Setaria (decreased by 33.66%, decreased by 6.90%, decreased by 26.80%, increased by 412.57%, increased by 1068.32%, increased by 9.20%, increased by 58.10%, decreased by 18.20%), the main material to resistant drought was Pro, SOD and POD. Artemisia gmelinii (decreased by 33.15%, decreased by 18.95%, increased by 29.64%, increased by 24.44%, increased by 20.06%, increased by 4.79%, decreased by 51.62%, decreased by 15.39%), the main material to resistant drought was Pro and SOD. Giraldii (decreased by 72.94%, decreased by 14.88%, increased by 47.70%, increased by 4.38%, increased by 40.73, decreased by 12.89%, increased by 9.01%, increased by 63.21%), the main material to resistant drought was Pro and POD. Grass bothriochloa (decreased by 13.95%, decreased by 2.78%, decreased by 25.69%, increased by 5.76%, decreased by 70.61%, increased by 0.26%, decreased by 6.85%, decreased by 30.58%), the main material to resistant drought was SOD. Lespedeza davurica (decreased by 21.47%, decreased by 4.69%, decreased by 11.42%, decreased by 4.33%, increased by 77.17%, increased by 3.63%, decreased by 19.29%, decreased by 33.29%), the main material to resistant was Pro and SOD. The results of Chlorophyll content, Membrane permeability and MDA content showed that Lespedeza davurica and Grass bothriochloa were little effect by water stress, Setaria, Giraldii and Artemisia gmelinii were great effect by water stress; and the results of Pro content and protective enzymes activity of antioxidant system showed that the way of six plant species to resistant drought was different.(4) Water stress had great effect on plant water consumption, which was decreased as water stress degree increased, and water consumption in July and August was increasd. Plants WUE under water stress treatment in order was Grass bothriochloa>Artemisia gmelinii>Setaria>Giraldii>Artemisia scoparia>Lespedeza davurica, which showed plant with high competitiveness, had a low WUE, and not have the advantage of production. Plants with strong ability to resistant drought must not have a high WUE.Under two plants specials mixed treatment, plant WUE was promoted under several water stress treatment, plants with well drought tolerance had a high WUE under severe stress to adapt their growth without hurt, the WUE of Grass bothriochloa and Lespedeza davurica mixed was the highest under several water stress treatment, which showed the well competitive strength in drought environmental. According to six plants mixed results, plants with small planting density had high WUE under several water stress treatment. Water consumption in 3d decreased as water stress time extended, and biomass decreased as planting density decreased. Due to the completions interspecific being slow under moderated and high water treatment, the hightest WUE appeared in 4 planting density treatment.
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