Colorectal carcinoma is the third most common malignancy among all carcinoma patients. Carcinoembryonic antigen (CEA) is used as a tumor marker for colorectal carcinoma patients as it is inexpensive, easily measured through serum tests, and can be repeated multiple times with minimal impact, however its use in the risk of colorectal adenocarcinoma is unclear. We aimed to investigate the relationship between CEA levels and the severity risk of grading in colorectal adenocarcinoma patients. There is a significant relationship between grading and CEA, namely, the higher the CEA, the worse the grading becomes. No significant difference was found between the CEA values in different grades, but the average value increases as the grading of colorectal carcinoma worsens. A CEA value of 8.45 serves as the cut-off point for worse differentiation, with a sensitivity of 61.8% and a specificity of 65.2%.