When a patient is diagnosed with gastric cancer and is hospitalized, the patient and the patient’s family will be anxious to have the surgery sooner and will complain that the doctor has prescribed too many tests. In fact, the pre-treatment evaluation is the basis for determining the treatment plan, through a series of tests, the patient’s disease will first be initially staged, and the doctor will decide the treatment plan, whether the treatment can be tolerated, the possible risks of the treatment, and have a preliminary estimate of the treatment results based on the disease staging. The doctor decides the treatment plan based on the stage of the disease, whether the treatment can be tolerated, the possible risks of the treatment and has a preliminary estimate of the outcome. Patients and family members should communicate carefully with the doctor after the test results are available in order to fully understand the disease. If a patient is admitted to the hospital and undergoes surgery without adequate evaluation, it may not be the best treatment choice, but only to meet the so-called “timely treatment” or “less tests to save money” of the patient and family, and we have seen many patients who did not even do CT, but had a gastroscopy result plus some routine tests. I’ve seen many patients undergo surgery without even having a CT, but with a gastroscopy result and some routine tests, which is a very irresponsible attitude no matter to whom. In addition to gastroscopy and biopsy, the pre-treatment evaluation includes the following items: 1. (1) Blood tests: routine blood tests, blood biochemistry, serum tumor markers, blood type, pre-transfusion tests, etc. (2) Urine, stool routine, fecal occult blood test. 2.Imaging examination. (1) Computed tomography (CT) scan: CT plain scan and enhanced scan have important values in evaluating the extent of gastric cancer lesions, local lymph node metastasis and distant metastasis, etc., and should be used as a routine method for preoperative staging of gastric cancer. In the absence of contraindications to the use of contrast agents, it is recommended to perform enhanced CT scan when the gastric cavity is well filled. The scanning site should include the primary site and possible metastatic sites. (2) Magnetic resonance imaging (MRI): MRI examination is one of the important imaging tools. It is recommended for those who are allergic to CT contrast or those who suspect metastasis on other imaging tests. MRI helps to determine the status of peritoneal metastasis and can be used as appropriate. (3) Upper gastrointestinal imaging: It helps to determine the scope and functional status of the primary gastric lesion, especially air-barium double contrast imaging is one of the common imaging methods to diagnose gastric cancer. For patients suspected of pyloric obstruction, water-soluble contrast agent is recommended. (4) Chest X-ray examination: it should include frontal and lateral phases, which can be used to evaluate whether there are lung metastases and other obvious lung lesions, and lateral phases can help to detect post-cardiac shadowing lesions. If lung metastasis is suspected, CT-enhanced scan is required. (5) Ultrasonography: It has certain value in evaluating the local lymph node metastasis of gastric cancer and metastasis in superficial areas, and can be used as a preliminary examination method for preoperative staging. Transabdominal ultrasonography can understand whether there are metastases in the abdominal cavity and pelvis of patients, especially ultrasonography can help identify the nature of lesions. (6) PET-CT: It is not recommended for routine use. It can be used as appropriate for metastatic lesions that cannot be clearly identified by conventional imaging. (7) Bone scan: not recommended for routine use. For patients with gastric cancer suspected to have bone metastasis, bone scan examination can be considered. 2.Other mainly for the examination of comorbidities and assessment of surgical risk, especially for elderly patients. For patients older than 60 years old, cardiac ultrasound and pulmonary function are routine examinations. (1) Electrocardiogram (2) Cardiac ultrasound (3) Pulmonary function