The main purpose of this study is to examine the fluctuation characteristics of natural Populus euphratica community.Field data were obtained by tally with contiguous grid quadrat method.Investigated contents include the community structure,dominant species,and the height structure,growth vigor and diameter structure of P.euphratica.Finally,the population structure and distribution pattern of P.euphratica in desert riparian forest were discussed on the basis of theoretical distributing model and assembling intensity index.The results shows:(1)The DBH class allocation of the P.euphratica populations mainly concentrated on the middle DBH class;Ⅲ～Ⅴ class was 66.62%;the seedling and young tree are insufficient; Ⅰ～Ⅱ class was 28.83% and Ⅵ class was 4.55%;the population spatial structure were not of integrity.It indicated that population show a decline stage in the early.The survivorship curve of the population conformed to the type of Deevey Ⅰ.(2)The height class structure of P.euphratica population had little difference,with range of 21.60%～31.07%,which belonged to growth-oriented population in the upper reaches of Trim River.The diameter class structure showed approximately normal distribution,which shows that the overall population is steadily increasing in middle reaches of Tarim River.The height class structure had great difference,with range of 12.50%～51.14%,the distribution of the diameter class was shown as a negatively skewed distribution,which belonged to stable type population.(3)The ground survey analysis indicated that P.euphratica distribution pattern shows aggregated distribution in the mainstream of the Tarim River,the aggregation intensity was different at various distance away from the river.P.euphratica was aggregated distribution in different stages and the aggregation intensity was different.The variations in spatial distribution patterns of populations in different habitats and at different growth stages were closely related to the biological and ecological characteristics of the species.