Abstract: Objective To study the tumor volume and lymph node metastasis ratio as a recurrence and metastasis index of stage Ⅲ colorectal cancer (CRC). Methods Clinical data about 120 stage Ⅲ CRC patients who underwent radical operation in our hospital from June 2005 to June 2008 were retrospectively analyzed. The patients were divided into tumor-free survival group and tumor metastasis group and followed up. Results Univariate analysis showed that the number of positive lymph nodes, lymph node ratio (LNR), N stage and TN ratio were related with the recurrence and metastasis of stageⅢ CRC (P＜ 0.05). Multivariate regression analysis showed that TN ratio, LNR and N stage were the independent factors for the recurrence and metastasis of stage Ⅲ CRC. Conclusion The TN ratio is an independent factor for the early prognosis of stage Ⅲ CRC, and can thus be used as an important index for the recurrence and metastasis of stage Ⅲ CRC after operation.