Objective To analyze predictive factors on survival in patients with completely resected high-risk Ⅱ/Ⅲ stage colorectal cancer after adjuvant chemotherapy.Methods According to random number table, 76 cases with completely resected high-risk Ⅱ/Ⅲ stage colorectal cancer after adjuvant chemotherapy were selected, who newly diagnosed and hospitalized in 2004. Their disease-free and overall survivals were followed up.Thymidylate synthase gene polymorphism and microsatellite instability were tested in these cases with microdissection combined with polymerase chain reaction and capillary electrophoresis. Correlation of these factors including clinical characteristics, thymidylate synthase gene polymorphism and microsatellite instability to survival was analyzed with SPSS13.0 software. Results Histologic grades and evaluated lymph node number had significantly difference between two groups of distinct prognosis (χ2 = 7.827, P =0.003 and χ2 = 9.265, P =0.018, respectively), which were also independent predictors on survival proved by COX regression analysis (χ2 = 40.472, P =0.000 and χ2 = 39.528, P =0.000, respectively).Kaplan-Meier survival analysis showed that the median disease-free and overall survival of poor-differentiated adenocarcinoma patients were significantly shorter than those of high and intermediate-differentiated ones (27.67 vs 61.13months, χ2 = 45.015, P =0.000 and 43.13 vs 64.21 months, χ2 = 35.514, P =0.000, respectively), as well, the median disease-free and overall survival of patients with the evaluated lymph node number less than 11 were poorer than those of more than 11 ( 45.65 vs 68.47 months, χ2 = 23.134, P =0.011 and 53.10 vs 70.18months, χ2 = 22.896, P =0.013, respectively).Conclusion Poor-differentiated adenocarcinoma and evaluated lymph node number less than 11 may be predictors on poor survival in patients with completely resected highrisk Ⅱ/Ⅲ stage colorectal cancer after adjuvant chemotherapy.