Abstract: Calamagrostis pseudophragmites is a perennial, rhizomatic, and typical clonal grass. Components and age structure of modules of C. pseudophragmites populations were studied at the end of the growing season in different habitats in the Yily River Valley area of Xinjiang, China. The populations were only composed of vegetative tillers in three habitats, while the fourth had both vegetative and reproductive ones. There were three age classes of tillers with an increasing age structure. There were two age classes of rhizomes and the 2nd was dominant. The potential populations consisted of winterness tillers, apical buds of rhizomes, and dominant buds growing upwards from tiller nodes. Each potential population had an increasing age structure but of all the age classes of buds, the 1st age was the most common. Livestock feeding and trampling all reduced storage of dry matter in tillers and rhizomes.