It has been reported that the immune status of patients with cancer were suppressed, especially those after surgery and adjuvant chemotherapy. Thus, immunotherapy may decrease the recurrence rate after surgery. CIK cells transfusion has been reported as an effect therapy in advanced cancers. In another retrospective study, investigators found that adjuvant CIK therapy would prolong the disease-free survival (DFS) for colorectal cancer patients. The purpose of this study is to determine wether adjuvant immunotherapy with CIK cells in patients with colon cancer after operation will prolong DFS, and overall survival (OS).