Stomach cancer is one of the common malignant tumors in China, and its incidence rate is the first among all types of tumors in China. It is important to be very alert to the early symptoms of gastric cancer to avoid delaying the diagnosis and treatment. Gastric cancer must be distinguished from gastric ulcer, simple polyps in the stomach, benign tumor, sarcoma, and chronic inflammation in the stomach. It is fashionable to differentiate from gastric fold hypertrophy, giant fold disease, gastric mucosal prolapse, pyloric muscle hypertrophy and severe fundic varices. The differential diagnosis mainly relies on X-ray barium meal angiography, gastroscopy and biopsy. 1.X-ray: The performance of gas-barium double imaging can clearly show the stomach outline, mucosal morphology, emptying time, peristalsis, the presence of filling defects, niches and so on. The accuracy rate of examination is nearly 80%. 2.CT examination: to understand the invasion of gastric tumor, the relationship with surrounding organs, and the possibility of resection. 3.B ultrasound: it can understand whether there is metastasis in the surrounding substantial organs. 4.Fiber endoscopy: It is the most direct, accurate and effective diagnostic method to diagnose gastric cancer. 5.Laboratory examination: early suspected gastric cancer, low free gastric acid or deficiency, such as decreased hemoglobin, red blood cell pressure, red blood cells, fecal occult blood (+). Low total hemoglobin, white/bulb inversion, etc. Water-electrolyte disorders, acid-base balance imbalance and other laboratory abnormalities. 6.Exfoliative cytology examination: some scholars advocate this examination when the clinical and X-ray examinations are suspicious of gastric cancer.