Potassium-solubilizing bacteria (KSB) often attach onto the surface of minerals, and secrete acid substances capable of dissolving insoluble nutrients, such as potassium, phosphorus, and silicon from the minerals, facilitating plant nutrients uptake. The functioning potassium solubilizing mechanisms of KSB are key for soil quality improvement and sufficient nutrient utilization that are essential for sustainable agriculture. Recently, mechanistic understanding of the KSB functions and their potentials on sustainable agriculture has become a hot spot of focus of the study on soil microbiology both in domestic and abroad, and this trend is likely to continue in the near future. Numerous studies have attempted to address the biological and/or physiological mechanisms of potassium-solubilizing processes (e.g., acidolysis, enzymolysis and polysaccharides complex dissolution, etc.), and to identify key factors regulating their performance in both lab-scale and field-scale experimental systems. Nevertheless, microscopic mechanistic understanding of the functioning biophysical interactions between KSB and soil minerals remains largely unknown, and remarks a key for untangling the black-box potassium-solubilizing processes. This paper reviews recent advances on KSB diversity and specification, and their implication performance, focusing on biofilm formation processes onto potassium-bearing minerals at single-cell level and the driving forces, and their consequent functions on soil potassium utilization. Numerous advanced analysis technologies and cutting-edge methodologies devoting on KSB investigation are summarized.