Abstract: Objective To assess the efficacy and the safety treated by radiotherapy for colorectal cancer (CRC) oligometastases. Methods CRC oligometastases treated with radiotherapy in our cancer center between January 2012 and December 2016 were included for clinical review. After follow-up and observation, survival analysis was conducted to evaluate the efficacy and safety of oligometastases in patients with colorectal cancer. Results In this study, 48 patients with colorectal cancer oligometastases were enrolled, and the number of metastases receiving radiotherapy was 88. The proportion of lung metastasis and liver metastasis was 45.83% and 29.17%, respectively. There were 26 cases (54.17%) of recurrence and metastasis after treatment, 22 cases (45.83%) occurred in the initial diagnosis of the disease. The 1-year local control rate and 2-year local control rate were 85.50% and 73.69%, respectively. Local failure rate reached 20.83%. The 1-year and 2-year overall survival rates (OS) were 84.29% and 58.32%, respectively. The PFS of patients at 1 year and 2 years were 44.01% and 22.29%, respectively. Univariate analysis showed that the P value of the PFS and OS were 0.038 and 0.041 in patients with Synchronous oligometastases compared with nonsynchronous oligometastases,suggesting that PFS and OS benefit significantly in patients with nonsynchronous oligometastases.Gender, age, number of metastases, induction chemotherapy, maximum diameter of tumors had no significant effect on OS and PFS. The side effects were mainly acute toxicity during radiotherapy. There were only 1 case in grade 3, and others were grade 1-2. No grade 4 or more serious toxicities caused death, and no long-term toxicity was observed. Conclusion Three-dimensional conformal intensity modulated radiotherapy for colorectal cancer oligometastases has definite efficacy and higher safety, which is worthy of clinical promotion and application.