Abstract: Objective To investigate the expression of EZH2 and H3K27me3 in esophageal squamous cell carcinoma (ESCC) tissues and their correlation with the clinicopathological parameters of ESCC patients, and evaluate their prognostic significance for ESCC patients. Methods The immunohistochemistry staining was used to examine the expression of EZH2 and H3K27me3 proteins in ESCC tissues and the para-carcinoma tissues. The correlation between EZH2, H3K27me3 expression and the clinicopathological parameters was analyzed. The correlation between EZH2 and H3K27me3 expression was also developed. Overall survival of patients was estimated by Kaplan-Meier method, and the differences between groups were compared by Log rank test. Results The expression rates of EZH2 and H3K27me3 in ESCC, para-carcinoma tissues were 70.8%, 44.6% and 47.7%, 26.2%, respectively. The expression of both EZH2 and H3K27me3 were positively correlated with histological grade and lymph node metastasis of ESCC patients, moreover, EZH2 expression was positively correlated with H3K27me3 expression. The 5-year overall survival of ESCC patients with EZH2 and H3K27me3 positive expression were significantly lower than those with EZH2 and H3K27me3 negative expression, respectively. The 5-year overall survival of ESCC patients with both EZH2 and H3K27me3 expression was significantly lower than those with EZH2 or H3K27me3 positive expression or negative expression of both. Cox regression analysis showed that lymph node metastasis, histological grade, EZH2 and H3K27me3 expression was the independent prognostic factor for ESCC patients. Conclusion Both EZH2 and H3K27me3 are highly expressed in ESCC tissues, and correlated with histological grade and lymph node metastasis of ESCC tissues. EZH2 and H3K27me3 may be the poor prognostic factors of ESCC patients.