The biosolubilization of potassium feldspar (K-feldspar) by potassium-dissolving microorganisms has become a hot research topic. However, the screening of highly efficient potassium-dissolving strains from the soils of mining areas has not been reported. In this study, 82 strains with potassium-dissolving ability were screened from soils collected from a K-feldspar mining area in Suizhou, Hubei Province, China. One of them, JX-20, was a gram-positive spherical bacterium with a smooth surface, which was identified as a new strain by 16S rRNA gene sequencing. Simultaneously, the influences of temperature, initial pH value, inoculation volume, incubation time, shaking speed, K-feldspar concentration, K-feldspar granularity, and the ammonium sulfate dose on the potassium releasing ability of the JX-20 strain were investigated. The results showed that the JX-20 strain had an obvious dissolution effect on K-feldspar. The optimum conditions for the JX-20 strain to remove potassium from K-feldspar were as follows: cultured at 28-30℃ for ten days, initial pH value of 7.4-8, 60 mL medium in a 250 mL conical flask, and 170 r/min shaking speed on a rotary shaker. The K-feldspar concentration, inoculation volume, K-feldspar granularity, and ammonium sulfate dose were 2 g/L, 20%, 0.02-0.03 mm, and 0.4 g/L, respectively. Under the above conditions, the highest corrosion efficiency of 39.75% was achieved.