Abstract: The variations,associations,relationships of different family groups and functional class groups of nine leaf traits from 35 plants of Ningxia,Northwest China were studied,to assess the adaptation of the 35 plants to their environment and to provide a scientific basis for discussion of restoration and reconstruction of arid region ecosystems. There were differences of leaf traits between the species,and according to the coefficient of variation,the nine leaf traits can be divided into three categories: high coefficient of variation (leaf thickness and leaf water uptake content),moderate coefficient of variation (percentage increase in leaf water content,leaf density,leaf succulence and specific leaf area),low coefficient of variation (chlorophyll content,leaf dry matter content and leaf water saturation deficit). The averages of leaf density,chlorophyll content and leaf dry matter content in annuals were highly significantly (P<0.01) lower than those in perennials,but the averages of specific leaf area in annuals was highly significantly (P<0.01) more than that in perennials. There were highly significant (P<0.01) differences in leaf density,leaf thickness,leaf succulence,leaf dry matter content and leaf water uptake content among the different family groups but there were no significant differences in specific leaf area,water saturation deficit,chlorophyll content and leaf water content. Leaf density,leaf thickness,leaf succulence,leaf dry matter content and leaf water uptake content could be the better traits for studying leaves in the different family groups.