The purpose of this study is to investigate efficacy and safety of intra-operative chemotherapy with 5-FU for colorectal cancer patients receiving curative resection. The hypothesis is intra-operative intervention might be the best timing for cancer cells killing by cytotoxic agents, when most of residual cancer cells may get a rapid growth after tumor debulking and may become more chemotherapy-sensitive. A three-step procedure is designed for intra-operative chemotherapy with 5-FU of 1500 mg/m2, including step 1 of intraluminal 5-FU injection with 1000 mg/m2 at beginning of resection, step 2 of 200mg/m2 5-FU injection into portal vein system via mesentery vein after tumor removal and finish of bowel reconstruction, and step 3 of 300mg/m2 5-FU left into the abdominal cavity before incision closure. The controlled arm receive curative resection only. All the other treatments will stick to the guidelines.