The natural Populus euphratica forests situated on Kaha, Shazihe, Qiala sections that located in the inner side of water conveyance embankments and Wusiman, Aqihe, Tieyizi section that located on the outer side were studied in this research. On the basis of setting sample plots, the study analyzed the Populus euphratica′s communities and populations structures and the growth information which was from the branches increment of Populus euphratica. Then we analyzed the influence of water conveyance embankments on the Populus euphratica′s communities and populations. So it will provide some scientific references for evaluating the influence of water conveyance embankments on the Populus euphratica objectively and protecting the Populus euphratica forests. The research results showed that: (1) there is great difference about the structures of Populus euphratica communities in the different section of middle reaches of Tarim River. The plant species and species diversity indices of Populu euphratica communities in the inner side of water conveyance embankments were higher than the outer side. And the species to have altogether in six sections were Populus euphratica, Tamarix ralnosissima, Phragmites australis and Glycyrrhiza uralensis. (2) The Populus euphratica populations in the inner side of water conveyance embankments had more saplings that were the DBH less than 2.5centimeter and less on the middle and old individuals, which belonged to growth-oriented population, when the populations on the outer side lacked saplings and had more middle and old age individuals, which belonged to declining type population. (3) Except for the Qiala section, the branch diameter increment of Populus euphratica in the middle reaches increased from 1998 to 2003, and it declined from 2004 to 2007. The analysis of the growth of Populus euphratica showed that there was significant difference between the inner and outer side of water conveyance embankments.