CEA is a commonly used tumor marker in clinic, the value is higher than 5ng/ml, and greater than 10ng/ml is a significant increase, which has a clear guidance significance. CEA is called carcinoembryonic antigen, which is a kind of glycoproteins, and the value will rise in all kinds of tumors, especially for intestinal malignant tumors, such as rectal cancer, colon cancer, the significance of guidance is clearer; the corresponding value is in the normal range of 0~5ng/ml, and the value of more than 5ng/ml belongs to the slight rise, and more than 10ng/ml belongs to the obvious rise, and the probability of malignant tumors will be increased significantly. Further investigation needs to be combined with imaging, endoscopy and pathological puncture biopsy to make a comprehensive judgment, after confirming the diagnosis of the condition, standardized treatment under the guidance of clinicians.