Abstract: Objective To clarify the biological function of IL-1RAP in glioma cells and its relationship with signal transducer and activator of transcription 3(STAT3). Methods The glioma cell line U251was transfected with IL-1RAP expression vector. Cell cycle and apoptosis of IL-1RAP-transfected U251cells wereaanalyzed by flow cytometry. STAT3 expression was analyzed by immunocytochemistry and co-immunoprecipitation. Colocalization of IL-1RAP and STAT3 was detected by immunofluorescence. Results IL-1RAP protein was localized in the nucleus of glioma cells.Compared with control group transfected with empty plasmid, IL-1RAP transfection caused the apoptosis(52.10±5.51)% vs.(7.57±0.54)%, P＜0.05 and cell cycle arrest of U251 cells(68.22±1.96)% vs.(38.31±7.22)%, P＜0.05. In addition, IL-1RAP and STAT3 were colocalized and may interacted to affect the prognosis of glioma cells. Conclusion IL-1RAP could inhibit the proliferation and promote the apoptosis of glioma cells, which may be related with its interaction with STAT3.