In order to analyze the spatial pattern of soil seed bank and its relation to environmental factors in the lower reaches of Tarim River,20 sampling plots were established.Seedling germination experiment was carried out and ordination technique(canonical correspondence analysis)was used in the study areas.Results showed that there were 16 species,belonging to 7 families in soil seed bank,among which tolerant-drought and salinity species were dominant.Most species occurred infrequently and soil seed bank density was lower compared with other desert regions.Groundwater depth,soil moisture content,electric conductance,pH,vegetation coverage all influence the distribution of soil seed bank.The relatio nship among the first axe of the CCA,groundwater depth,standing vegetation coverage,and soil moisture content were significant,indicating the role of water availability factor.The relationship between the second axe of the CCA and the electric conductance was significant,indicating the role of salinity factor.Based on the above five environmental factors,16 species of soil seed bank were divided into four groups.