To explore the function roles of K+-efflux-antiporters KEA1 and KEA2 in Arabidopsis thaliana, wild type and kea1kea2 knock-down mutants of Arabidopsis thaliana were used as materials to investigate the effects of KEA1 and KEA2 on plant growth and development. Phenotypic analysis, propidium iodide staining to observe the structure of roots, high performance liquid chromatography to determine endogenous sugar content, transcriptome sequencing and qRT-PCR to analyze the relative expression levels of related genes, histochemical staining to detect the distribution of superoxide anion in leaves were performed respectively. The results showed that the root length of the kea1kea2 mutant was significantly shorter than that of the wild-type Col-0 plant in the absence of sucrose. Further observation showed that compared with the wild-type, the root meristem zone of kea1kea2 mutant was shorter, the endogenous sucrose content was decreased, and more O2·- was distributed in the leaves of the kea1kea2 mutant. However,when 30 g·L-1 sucrose was exogenously added, there was no significant difference in root length between the wild-type and kea1kea2 mutant. Transcriptome analysis revealed that the expression of many key genes involved in sucrose signals and root growth were repressed in the kea1kea2 mutant. In summary, the results suggested that sucrose might affect AtKEA1and AtKEA2 to regulate root growth in Arabidopsis seedlings.