Abstract: In order to study the response characteristics and relationship among main factors of Populus euphratica after water delivery in lower reaches of Tarim River, Xinjiang of northwestern China, the diameter at breast height(DBH), treecrown and height of P. euphratica were investigated, and their correlation was analyzed. The results showed that the treecrown and height decreased with the increase of distance from river, while the changes of DBH had no regularity. Field data was grouped by diameter class, and the correlation analysis of treecrown, DBH and height showed that there was a significant correlation among them. The precision of model established between DBH and height reached 90.08%. The fitting accuracy of models decreased gradually with the decline of groundwater level. The average precision of the models established between treecrown and DBH was 81.37%, and the fitting precision of them did not show obvious regularity as the changes of groundwater level. All of these were regarded as the mancifestation of P. euphratica responding to groundwater level after a long term drought stress.