Abstract: The experimental results of two years indicated that water potential and relative water content of leaves of wheat cultivars with strong drought resistance were higher than that of the cultivars with weak drought resistance under soil water stress. Osmotic potential and water potential were subjected to linear relation, osmotic potential changed 0.71-0.93 unit when water potential changed one unit, and that Log osmotic potential in relation to Log relative water content was a broken line composed of two straight lines. The first straight line showed that the decrease of osmotic potential was completely compensated with osmotic adjustment. The second straight line showed that the decrease of osmotic potential resulted from concentration due to cell losing water. The ability of osmotic adjustment was as follows. Qinmai NO. 3 >Changle NO. 5>Shannong NO.587>Jinan NO.13>Yanhong NO.15>Lumai NO.5.