The morphology, vegetation, and soil physical and chemical properties of two vegetation-dunes located in different areas of the southern margin of the Mu Us Sandy Land were investigated. The aims of the study were to examine the similarities and differences of plant communities between parabolic dunes and Nitraria tangutorum nebkhas under the same environmental conditions, and to elucidate the relationship between plant community differences and dune morphology. The horizontal scale of the parabolic dunes was 12-23 times greater than that of the nebkhas, whereas the number of species on the two dune types was equivalent. The plants on parabolic dunes and N. tangutorum nebkhas comprised 12 families, 31 genera, and 39 species, and 12 families, 30 genera, 33 species, respectively, with the plants mainly belonging to four families:Asteraceae, Chenopodiaceae, Gramineae, and Leguminosae (more than 70%). There were 17 mutual species and the similarity index of the plant communities was 0.66, although there were differences in the constructive species and there was a lower degree of overlap of the dominant species. Seven plant associations were identified and could be classified into the psammophyte community and the saline-alkali-tolerant community on different parts of the parabolic dunes. In contrast, N. tangutorum was the only constructive species of the nebkha plant community, and the dominant species were Artemisia ordosica, Agropyron cristatum, Bassia dasyphylla, Agriophyllum squarrosum, and Setaria viridis. The spatial variability in soil moisture, pH, total salt content, and intensity of sand-drift activities caused by dune morphology promoted the differences in plant communities between parabolic dunes and N. tangutorum nebkhas.