Abstract: In the Paper, Plasmolemma Permeability in desert Plants and their effects on water Stress are discussd. The result shows that che desert Plants contain a lot of electrolytic conductivity. There exist few electrolytic materials and total electrolytic conductivity. The relationship between the total electrolytic conductivity and mesophyllous degree is close. The effect of Plasmolemma on water stress in guite sensitive. Plasmole-mma Permeability will be increased when water content of Plant tissue decreased.