Abstract: Recently, in China the application of small amount of rare-earth nitrates or chlorides to the field has proved that REenhanced the growth and development of crops and increased yields. In order to understand the functions of rare earth elements in plant growth, we must first of all establish a sensitive analytical method for the determination of trace amounts of RE in the plants. In the present investigation we have used the sensitive single-sweep polarographic waves suggested by our research group to determine the RE contents in spinach, tea and pineleaves taken from different districts. The results showed that those plants growing near the RE mines (Jiangxi) have higher content of RE (ranging from 1.7 to 37.8 μg/g dry material basis) than those from other places. Wu Zhaoming et al of Institute of Botany, Academic Sinica, applied La-nitrate in water culture of cucumber and cut down the leaves from different parts of the plant for analysis. We found that the contents of La in the young leaves are much more than that in the old leaves. This result is in accordance with general role of distribution, that is more nutrient elements gathering in the growing center of the plant. This preliminary information is very useful for further study to find out whether RE is an essential nutrient element or not and what is its physiological function in the growth of the plant.