Immunohistochemical staining of the gastric mucosa is accurate for diagnosis, and pathology is the gold standard for diagnosis. The pathologist slices and stains the gastric mucosa biopsy specimen, and diagnoses the gastric mucosal lesions under the microscope. Different staining methods have certain differences in detection results, of which immunohistochemical staining is a highly sensitive and specific staining method, which is the “gold standard” of histological detection. The advantages of immunohistochemistry are specificity, sensitivity, simplicity, rapidity and low cost, so it is widely used in hospitals. It is widely used in the diagnosis of malignant tumors, determination of primary foci of metastatic tumors, tumor typing, detection of small metastatic foci of tumors, and assisting in the selection of tumor treatment plans.