Objective: To explore the role and mechanism of epiregulin (EREG) in clear cell renal cell carcinoma (ccRCC)，and to find biomarkers and therapeutic targets for ccRCC. Methods: Based on the data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases，the correlation between the expression level of EREG in ccRCC tissues and the clinical staging and survival of ccRCC patients was analyzed. The samples of 6 ccRCC cases treated in the Second Affiliated Hospital of the Air Force Medical University were collected. The expression of EREG was confirmed with immunohistochemistry and quantitative real-time polymerase chain reaction (q-PCR). The effects of EREG overexpression on the proliferation，cell cycle and apoptosis of ACHN cells were verified with CCK-8 and flow cytometry. Finally，the expressions of EREG，epidermal growth factor receptor (EGFR) and the downstream pathway proteins were detected with Western blotting. Results: Based on the databases，it was found that the expression of EREG in ccRCC samples was higher than that in adjacent tissues，and there was a positive correlation with the clinical stage. Survival analysis showed that high expression of EREG was a risk factor affecting the prognosis. The results of immunohistochemical staining and qPCR revealed that EREG was highly expressed in ccRCC. Flow cytometry showed that EREG overexpression promoted the proliferation of ACHN cells，enhanced cell cycle，and inhibited apoptosis. In addition，Western blotting suggested that EREG promoted the expressions of EREG，EGFR and the downstream proteins. Conclusion: The expression of EREG is associated with the prognosis of ccRCC patients. In vitro cell experiments have shown that it can promote the proliferation of ccRCC cells and inhibit their apoptosis，thereby leading to the progression of ccRCC. It can serve as a potential biomarker for prognosis prediction and a drug development target for ccRCC patients.