Abstract: This paper deals with the water regime of the plant communities on sands at the Toutao lake basin of Alashan desert, Ningsia. By examining the relationship between the environmental conditions and the transpiration rates and green- part production of 13 species of plants mainly of in 3 plant communities, the results obtained may be briefly summarized as follows: 1) Rates and daily changes of transpiration for different species are closely related to the morphological and ecological characters of the plants under experimentation. Xerophytes seem to be characterized by their intense transpiration and daily changes, as expressed by the dior poly-peak curves, while in the succulent xerophytes occur the least transpiration and slow daily change, as shown by a mono-peak curve. The transpiration intensity of mesophytes gives intermediate type as demonstrated by the mono-or dipeak curve. Although eurytopic mesophytes have the greatest intensity of transpiration, but their daily changes are similar to those of mesophytes. The intensity of transpiration of plants is affected by environmental conditions as well as by the phenological phase. 2) Water loss of plants varies with the different species and plant communities. It is a function of the rates of transpiration and green-part production of plants, the latter playing the greatest role. In addition water loss in transpiration of plants is also affected by the content of soil moisture and the amount of precipitation. 3) The amount of water loss in the transpiration of plants growing on semi-mobile sands is well balanced with the content of soil moisture.