Abstract: Objective : To investigate the expression of Fas ligand in colon adenoma, col-orectal cancer and liver metasetase, and determine the relationship between FasL expression and tumor biological behaviors. Methods : FasL expression was detected by using immunohistochemical method.The staining characteristics were compared with degree of differentiation, serosal invasion and Duke's stage. Results : FasL expression upregulate in colorectal cancer, significant linear re-lationship was found between FasL expression and Duke's stage, lymph node and liver metastases. All liver metastases express FasL. Conclusion : FasL expression upregulate in colorectal cancer, indicate the importance of FasL in the pathogenesis and progression of tumor cells.