The invention discloses a method for quantifying a tumor immune state based on radiomics, wherein the method comprises the following steps: S1, collecting clinical information, immunohistochemical characteristics, overall survival OS and disease-free survival DFS of tumor patients; S2, obtaining a CT image sample group of solid tumors; S3, randomly dividing the patients into a training set and a test set in proportion; S4, calculating the immunoscore by an immune marker, and dividing the patients into a set with high immune state and a set with low immune state; S5, segmenting an interest region, and extracting radiomics characteristics of the solid tumors in the interest region; S6, screening the radiomics characteristics related to the immune state from the radiomics characteristics in the training set, and training a prediction model; and S7, predicting the image immunoscore of the tumor patients, obtaining the image immune state, and then predicting the DFS and the OS in the patients. The immune state of the solid tumors such as colorectal cancer, lung cancer, gastric cancer and breast cancer is predicted by the CT image characteristics, and the analysis of pathological sections and immunohistochemistry is reduced or avoided.