Abstract: Objective 　This study was designed to evaluate the expression and it s significance of colorectal carcinoma-associated antigen LEA in colorectal carcinoma cells through the comparison of a new monoclonal antibody (ND-1) and anti-CEA monoclonal antibody. Methods 　Expression of L EA and CEA in colorectal carcinoma cells was detected with immunocytochemistry and flow cytometry . The specificity of LEA and CEA in colorectal cancercells was analyzed by ELISA, and to detect the expression of LEA in colorectal cancer tissues with immunohistochemical method. Results 　Flow cytometry detection showed that positive peak mean fluorescence intensity was gradually decreasing in the expression of L EA in CCL-187, CX-1, CLoneA and CCL-229, and stronger than that of CEA( P < 0. 01) . LEA was highly expressed in the well differentiated colorectal cancer cells of CCL-187 and CX-1, and its expression amount in low invasive cell lines of CCL-187 and CX-1 was higher than high invasive ones of CLoneA and CCL-229 ( P <0. 01) . EL ISA analysis revealed that monoclonal antibody ND-1 had st ronger specific binding activity to the colorectal carcinoma cell lines as compared to the CEA ( P < 0. 01 ) . The expression of L EA was decreased following the drop of tumor differentiation degree ( P < 0. 01 ) and exhibited higher selectivity in well differentiated colorectal cancer ( P <0. 01) . CEA had similar selectivity in well, moderately, and poorly differentiated colorectal cancer ( P >0. 05) . Conclusion 　LEA is more specific well differentiation colorectal carcinoma-associated antigen. LEA may be related to the differentiation degree, invasiveness and malignancy degree of cancer cells. LEA can be used as a useful measurement for the early diagnosis and malignancy degree of colorectal carcinoma.