Abstract： Objective To explore the mechanism of gene transcription suppression of E-box element composition by analyzing the two adjacent E-box elements of GCLC gene in rats. Methods The rat GCLC deletion mutants of E-box element (-804～-799) and two E-box elements (-804～-799,-729～-724)were cloned by PCR point-directed lacking and constructed into pGL-3 enhancer vector which includes luciferase reporter. Using LipofectamineTM 2000,GCLC-Luc and its E-box deletion mutants were transfected into rat bronchial epithelial cells (RTE) and rat alveolar epithelial cells(CCL-149). The luciferase activities of different transfected cells were compared to analyze the impact of E-box on GCLC gene transcription activity. Results The E-box deletion mutants of GCLC-Luc were successfully constructed. The luciferase activity of RTE and CCL-149 transfected with GCLC-delhE-box-Luc and GCLC-DdelE-box-Luc was significantly higher than that of GCLC-Luc-transfected cells,and roughly equivalent to that of GCLC-delE-box-Luc-transfected cells. E-box element exerted a suppressive impact on the transcription expression of GCLC gene in primitive state. Conclusions Two E-box elements are able to suppress the transcription regulation of GCLC gene by transcribing factor and element composition.