The Minqin oasis is located in the northwest Hexi Corridor, and the northern, western, and eastern edges are surrounded by the Tengger and Badain Jaran deserts. To manage sand and prevent sandstorms, large tracts of Haloxylon ammodendron plantations were previously planted on the fixed and semi-fixed sand dunes of the Minqin oasis fringe. At present, parts of the H. ammodendron plantations, especially those close to the oasis, have presented with a degradation phenomenon due to multiple affecting factors. To ascertain the changes in soil seed banks and their relationships with aboveground vegetation during the degradation process of H. ammodendron plantations, some tracts of H. ammodendron plantations planted in 1987 were divided into no degradation (ND), slight degradation (SLD), moderate degradation (MD), and serious degradation (SD) stages, according to the growth status of these plants and their seedlings, as well as the coverage of biological soil crust. In the present study, the species composition, density, and species diversity of soil seed banks and their relationships with aboveground vegetation were studied, with field monitoring and indoor germination methods. The results showed that 1) with an increased degree of degradation of H. ammodendron plantations, the number of woody plants in the soil seed banks first decreased rapidly and then remained stable, and the number of herb plants in the soil seed banks, first increased rapidly and then decreased slowly, so that the peak emerged at the SLD stage. At the same time, dominant species in soil seed banks presented a succession trend from typical psammophytes to xerophytes, and the species similarity coefficients of soil seed banks and aboveground vegetation, as calculated by Jaccard's similarity coefficient, appeared to increase from ND to SLD and then decrease from SLD to SD. 2) The soil seed bank density of herb plants rapidly increased their stage of degradation from ND to SLD and slowly decreased from SLD to SD, while the soil seed bank density of woody plants has been increasing continuously and dramatically. The densities of herb plants and woody plants in the SLD, MD, and SD stages were 2.57 and 5.25, 2.32 and 11.38, and 2.28 and 14.74 times higher than that of ND, respectively. There was a positive correlation between the species in soil seed banks and aboveground vegetation, such that this relationship for herb plants can be described with a logarithmic curve of y=aln (x) + b (a ≠ 0), and for woody plants may be described with a quadratic curve of y=ax² + bx + c (a ≠ 0). 3) With the evolution from the SLD stage in H. ammodendron plantations to the SD stage, some species diversity indices, such as D_ma, D_sim, H', and J_sw, of herb plants in soil seed banks were initially obviously stable and then showed significant change, while the indices of woody plants showed continuous change. In addition, some obvious differences have been presented between trends of these indices in soil seed banks and in aboveground plants, while the degrees of change in soil seed banks were similar to those of aboveground plants. The changes in trend in the indices of woody species in soil seed banks were completely consistent with those in the indices of aboveground plants; however, the degrees of change in soil seed banks were smaller than those in the aboveground plants. These findings suggest that the degradation of H. ammodendron plantations is a succession from psammophytes to xerophytes, there is a strong interdependence between soil seed banks and aboveground vegetation, and soil seed banks in the degrading plantations will have a stronger potential for vegetation recovery due to the increase in seed bank stocks of some species, which is a response to increase the stability of the plant communities.