Colorectal cancer is a common malignant tumor of digestive system, and its incidence rate and mortality are increasing year by year. TNM staging system is the most commonly used tumor staging system in the world at present, but its staging standard is only based on the characteristics of tumor cells themselves, which cannot be included in the overall immune situation of patients, and the system has gradually showed insufficient guidance for the prognosis of patients. Therefore, based on the quantitative analysis of immune cells in tumor microenvironment, an immunoscore system was proposed. In recent years, many studies have confirmed that the immunoscore system can more accurately evaluate the clinical prognosis of colorectal cancer patients, and shows better effect than TNM staging. In addition, the immunoscore system also plays an important role in adjuvant radiotherapy and chemotherapy and in evaluation of efficacy of immunotherapy, etc. It can further optimize the TNM staging system and risk stratification, which is conducive to the development of individualized treatment plans for cancer patients. This article reviews the research progress of immunoscore system in the prognosis and efficacy evaluation of colorectal cancer patients.