〔Abstract〕 Objective To search for new biomarkers to predict prognosis in colorectal cancer(CRC) patients. Methods A prognostic model was developed for colorectal cancer with immune-related genes from the cancer genome atlas(TCGA) database using one-way Cox regression analysis and least absolute shrinkage and selection operator(LASSO) regression analysis. Moreover, the immune infiltration characteristics of patients in high and low risk groups was compared by sstimation of stromal and immune cells in malignant tumor tissues using expression data(ESTIMATE) and cell-type identification by estimating relative subsets of RNA transcripts(CIBERSORT). In addition, the expression levels of immune checkpoints were analyzed in patients from different risk groups. The sensitivity of patients in the two risk groups to chemotherapeutic agents was also compared based on genomics of drug sensitivity in cancer(GDSC). Results It was found that the prognostic model constructed based on immune genes could better predict the overall survival(OS) of CRC patients, and the results showed area under curve(AUC) values of 0.764(95%CI:0.751-0.793), 0.773(95%CI:0.761-0.779), and 0.760(95%CI:0.742-0.774) for 1-, 3-, and 5-year OS, respectively. Patients in the low-risk group had higher expression levels of immune checkpoints and more abundant immune cells such as T cells(P<0.001), dendritic cells(P<0.001), macrophages(P<0.001), neutrophils(P<0.001). Patients in the high-risk group might be more sensitive to some chemotherapeutic agents such as axitinib, imatinib, methotrexate, pazopanib, rapamycin, sunitinib and tasigarnib. Conclusion A prognostic model based on 19 immune genes was effective in predicting the prognosis of CRC patients. The number and activity of immune cells in the immune microenvironment in different patients may be an important factor influencing their response to immunocheck inhibitors and chemotherapeutic agents.