Potassium voltage-gated channel subfamily A regulatory beta subunit 2 (KCNAB2) is a potassium voltage-gated channel subfamily A member that plays a role in non-small cell lung cancer (NSCLC). However, its functional impact and mechanism in NSCLC are not fully understood. Here, we analyzed its effects on NSCLC cell behaviors and the underlying mechanism.mRNA expression levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR),(qRT-PCR), while protein expression was quantified by western blotting blot analysis or immunohistochemistry assay. NSCLC cell proliferation, migration, invasion, macrophage polarization, and apoptosis were evaluated through cell-based assays including cell counting kit-8 (CCK-8)(CCK-8) assay, flow cytometry, Tunel assay, wound-healing assay, and transwell invasion assay. The role of FTO alpha-ketoglutarate dependent dioxygenase (FTO)-mediated(FTO)-mediated m6A methylation in the regulation of KCNAB2 expression and their impacts on NSCLC cell behavior and M2 macrophage polarization were assessed through m6A RNA immunoprecipitation assay and rescue experiments. Xenograft mouse model assay was used to determine the effect of KCNAB2 on tumor formation in vivo.in vivo.KCNAB2 expression was downregulated and FTO expression was upregulated in NSCLC tissues and cells when compared with controls. Moreover, the expression of KCNAB2 was found to be lower in stage III NSCLC patients compared to those at stages I and II, and it was also lower in patients with positive lymph node metastasis compared to those with negative lymph node metastasis. Overexpression of KCNAB2 inhibited NSCLC cell proliferation, migration, invasion, and M2 macrophage polarization, while inducing cell apoptosis. These effects were mediated, at least partially, by inactivating the phosphoinositide 3-kinase (PI3K)/AKT(PI3K)/AKT pathway. Moreover, ectopic expression of KCNAB2 delayed tumor formation in vivo. FTOin vivo. FTO was found to mediate m6A methylation of KCNAB2, and knockdown of FTO resulted in the upregulation of KCNAB2 expression, leading to inhibition of NSCLC cell behavior and M2 macrophage polarization.KCNAB2 overexpression inhibited NSCLC cell behavior and M2 macrophage polarization by inactivating the PI3KPI3K/AKT/AKT pathway. Furthermore, FTOFTO-mediated-mediated m6A methylation was involved in the regulation of KCNAB2 expression in NSCLC. These results enhance our understanding of the role of KCNAB2 in NSCLC and suggest its potential as a therapeutic target.