Squamous cell carcinoma-associated antigen is a tumor marker that has good specificity and was first used to screen for cancer. It is mainly used to express squamous epithelial cells of the vulva, vagina and cervix. When it is high, it is usually seen in patients with malignant tumors, such as cervical squamous carcinoma, non-small cell lung squamous carcinoma, as well as head and neck, gastrointestinal, and urinary tract tumors. Of course, a high squamous cell carcinoma-associated antigen does not necessarily mean that the patient has squamous carcinoma. Some benign lesions may also lead to an increase in the associated antigen, such as tuberculosis, renal failure, pneumonia, hepatitis and liver cirrhosis, which are mainly due to the specific reaction of the body. Therefore, the sensitivity and specificity of squamous cell carcinoma-associated antigen for the auxiliary diagnosis, recurrence monitoring and prognosis of squamous cell carcinoma are not high, and other related tests should be improved. When squamous cell carcinoma-associated antigen is continuously elevated or at a high level, it should be examined by ultrasound, magnetic resonance imaging, CT, gastroscopy, etc. to determine whether it is caused by cancer and to treat it accordingly to avoid delaying the disease.