Abstract: Soil acidification is one of the main limitation factors affecting vegetation restoration in mining wastelands. Neyraudia reynaudiana can grow normally in the wasteland of rare earth mines with extremely serious soil acidification, indicating that it has specific morphological and physiological mechanisms. In order to reveal these mechanisms, a one-pot acid stress experiment was designed with four different pH levels (3.5, 4.5, 5.0 and 5.6) and the growth indices, biomass, antioxidant enzymes and MDA content of N. reynaudiana were measured. The results showed that N. reynaudiana grows normally in soil with pH 3.5, suggesting a strong resistance to acid stress. With the increase of soil pH, growth indices such as plant height, leaf length, number of leaves, tiller number, root length, root volume, root surface area and root diameter at first increased and then decreased, demonstrating that the low acid stress had a promotion effect on N. reynaudiana growth. In addition, all the growth indices for N. reynaudiana reached their peak under the pH 4.5 treatment, suggesting that this is the most suitable soil pH level for the species. N. reynaudiana adapts to acid stress by accelerating the root diameter growth rate and increasing the biomass allocation of the root. Our research also indicated that the antioxidant enzymes of N. reynaudiana were inhibited under acid stress.