One mineral-weathering Bacillus strain was isolated from the surface of weathered potash trachyte and was identified as Bacillus thuringiensis based on the physiological and biochemical traits and 16S rDNA sequence analysis. The dissolution of feldspar by strain E31 and the mechanism involved as well as the biological characteristics were characterized. The results showed that strain E31 could weather feldspar and release elements from the mineral. The concentrations of K, Fe, Ca, and Al were increased by 19.6%–25.6%, 1–12.5 times, 10.4%–47.2% and 1.2–4.5 times in the presence of strain E31 compared with the controls respectively during the mineral weathering process. pH value, gluconic acid content, and cell numbers in the culture medium were 3.62–3.80, 61–1 794 mg/L, and (8.7–16.1)×10⁶ cfu/ml, respectively, in the presence of strain E31, suggesting that strain E31 could promote the mineral weathering by increasing the production of organic acids in the culture medium. Furthermore, E31 strain has the ability to produce IAA and siderophores in culture medium and also has the characteristics of acid or alkali and salt tolerance and temperature resistance.