There is not an absolute relationship between tumor markers and pancreatic cancer, e.g., certain pancreatic cancer patients may not express tumor marker antigens and thus exhibit normal tumor marker levels. The diagnosis of pancreatic cancer requires a combination of symptoms, serum tumor markers, imaging and pathology, but the definitive diagnosis relies on pathology. Commonly used tumor markers for pancreatic cancer include CA199, CEA, CA50, etc., with different positive rates. 1. Serum CA19-9 is currently the most commonly used diagnostic marker for pancreatic cancer, with a sensitivity of 79%~81% and a specificity of 82%~90% for diagnosing pancreatic cancer. 2. About 10% of pancreatic cancer patients are Lewis antigen-negative blood structure, such patients do not express CA19-9 and need to be combined with other tumor markers to assist in diagnosis. The specificity of carcinoembryonic antigen in diagnosing pancreatic cancer is similar to that of CA19-9, but the sensitivity is only 44.2%. 3. Elevated CA125 is associated with early postoperative distant metastasis of pancreatic cancer, which to a certain extent reflects the metastatic potential of the tumor and its related load, especially for CA19-9 negative pancreatic cancer population, CA125 has a certain prognostic value. 4. Other commonly used clinical tumor markers include CA50, CA242, CA724, etc. Their combined application can help improve the diagnostic sensitivity and specificity, but they still need to be supported by high-level evidence. In conclusion, tumor markers are not the gold standard for diagnosis and have no absolute relationship with certain sensitivity. Therefore, patients with pancreatic cancer may have normal levels of tumor markers; comprehensive imaging and pathological examinations are needed to make a judgment. If pancreatic cancer is suspected or diagnosed, it is recommended to go to regular hospitals for comprehensive assessment of the condition and follow the doctor’s instructions to cooperate with the treatment, so as not to delay the condition.