Abstract: In recent years great progress has been made on the plasma membrane potassium ion transporters in plants with the significant development and wide application of molecular biology techniques. So fat many genes concerning the plasma membrane potassium ion transporters in plants have been cloned. Researches indicate that these plant potassium ion transporters can be divided into two groups: potass ium ion carriers and channels. The potassium ion channels can be further divided into three groups: inwardly rectifying K+ channel α subunits, K+ channel β subunits, and outwardly rectifying K+ channels. In this article, the research progress on the characterization, structure and function of the plasma membra ne potassium ion transporters are reviewed.