Carbon nanoparticles (CNPs) have been reported to boost plant growth, while the mechanism that CNPs enhanced potassium uptake for plant growth has not been reported so far.In this study, the function that CNPs promoted potassium uptake in BY-2 cells was established and the potassium accumulated in cells had a significant correlation with the fresh biomass of BY-2 cells. The K accumulation in cells increased with the increasing concentration of CNPs. The K influx reached high level after treatment with CNPs and was significantly higher than that of the control group and the negative group treated with K channels blocker, tetraethylammonium chloride (TEA). The K accumulation was not reduced in the presence of CNPs inhibitors. In the presence of potassium channel blocker TEA or CNPs inhibitors, the NKT1 gene expression was changed compared with the control group. The CNPs were found to preferentially transport K than other cations determined by rectification of ion current assay (RIC) in a conical nanocapillary.These results indicated that CNPs upregulated potassium gene expression to enhance K accumulation in BY-2 cells. Moreover, it was speculated that the CNPs simulated protein of ion channels via bulk of carboxyl for K permeating. These findings will provide support for improving plant growth by carbon nanoparticles.