Objective To investigate the relationship between immune condition and stages of tumor in patients with coloreetal cancer by detecting the activites of peripheral blood T cells and NK cells. Methods The activites of T cells and NK cells in peripheral blood from 90 patients with cancer of colon and 40 healthy controls were detected by flow cytometry. Results The CD3+ ratio,CD4+ rati-o,CD4+/CD8+ and NK cells were decreased in cancer of colon group. CD8+ ratio was increased com-pared with that of healthy control group. This chang became more significant following by accreseence of Dukes classification. Conclusion The cellular immune function disorder exists in cancer of colon pa-tients which a aggravation with the pathogenetic condition progress.