Purpose To investigate the clinical pathology significance of epithelial cellular adhesion molecule (EpCAM, CD326) expression in colorectal carcinoma cells. Methods Flow cytometry and immunofluorescence assay were used to detect EpCAM expression in 55 cases of fresh colorectal cancer tissues and adjacent normal mucosa. The percentage of positive cells (PPC) and mean fluorescence index (MFI) were calculated. Correlation of EpCAM expression with DNA ploidy change and its value were investigated in the early diagnosis of colorectal cancer. Results The values of PPC and MFI were significantly higher in colorectal carcinoma tissue than that in the normal colorectal tissue [(PPC: (83.48 ± 7.07)％ vs (43.56±5.29)％, t =39.22, P＜0.001. MFI: 28.90(19.60-45.89) vs4.89(3.79-6.28), Z=-6.45, P＜0.001) ]. There were also significant differences (P＜0.01) in the values of PPC and MFI between invasive type and ulcer types, between well-and moderately-differentiated and poorly-differentiated cancers, between Dukes stages A + B and C + D, (between pTNM stages I+ II and III + IV, between pTl + T2 and pT3 + T4, and between pNO and pNl. DNA content analysis showed that DNA polyploid was detected in 39 of 55 colorectal carcinoma (70.90％ ). The DNA index (DI) and ploid were correlated with differentiation degree and Dukes stages, but uncorrelated with lymph node metastasis. At the same time, in the EpCAM positive cases, DI was increased with increased expression of EpCAM (r = 0.668, P =0.000) and the proliferation index of cells in S phase ratio(Sphase fraction, SPF) (r1 =0.664, P1 =0.000, r2 =0.651, P2 = 0.000 ). Conclusion EpCAM expression is obviously upregulated in colorectal carcinoma, and it is closely correlated with the invasion, metastasis and proliferation of tumor cells. The combination of EpCAM expression and DNA content analysis provides references to the early diagnosis and prognosis evaluation in colorectal carcinoma.