Objective To explore the influence of EGFR gene interfering on the radiosensitivity of esophageal squamous cells.Methods Three kinds of siRNAs including three random sequences of positive EGFR siRNA (EGFR siRNA1、EGFR siRNA2、EGFR siRNA3),random sequence of negative EGFR siRNA,and blank control were transfected into Eca109 cells by lipofectamine.Cell proliferation was detected by Cell Counting Kit-8 assay.Protein and mRNA expressions of EGFR were detected by Western blot and RT-PCR,respectively.The ability of cell clone formation was used to evaluate the combination effect of X-rays and EGFR siRNA on the radiosensitivity.Results The positive expression rate of the EGFR mRNA in the Eca109 ceils transfected with EGFR siRNA1,EGFR siRNA2,EGFR siRNA3 was 26.74％,9.52％,4.61％,respectively,which was significantly lower than 42.44％ in the control cells transfected with blank siRNA (F =112.11,P ＜ 0.01).Meanwhile,the EGFR protein expression was reduced by 72.84％,53.01％ and 56.21％ after interfering of siRNA1,siRNA2,and siRNA3,respectively.CCK8 assay showed that the proliferation of Eca109 cells was decreased by 28.2％ since the siRNA interference.Moreover,the D0,Dq and SF2 of the combined treatment group were lower than those of irradiation alone group and the sensitization enhancement ratio was 1.50.Conclusions EGFR siRNA can effectively inhibit EGFR gene expression and enhance the radiosensitivity of Eca109 cells.