Abstract: In recent years, the diagnosis and treatment of adenocarcinoma of esophago-gastric junction (AEG) has attracted more and more clinical attention. At present, there are two kinds of definitions and classifications. One is about AEG, proposed by the Siewert from Germany, the other is about esophagogastric junction cancer, proposed by the Nishi from Japan, and the former is adopted in China. The authors analyze the differences and shortcomings in definition and classifi-cation between the Siewert and the Nishi, and propose a modified classification based on the histo-pathology of the esophagogastric junction in China (squamous cell carcinoma accounts for the majority in the lower esophageal segment and adenocarcinoma is rare), which is completely different from Western countries such as Europe and America. In this modified classification, malignant tumors within 3 cm above and below the esophagogastric junction are defined as esophagogastric junction cancer(including squamous cell carcinoma, adenocarcinoma, etc.), and tumor center above or below esophagogastric junction are defined as type Ⅰ and type Ⅱ. If the tumor center is located at esopha-gogastric junction, squamous cell carcinoma is defined as type I, and adenocarcinoma is defined as type Ⅱ. According to this definition and classification, the authors discuss the surgical approach, the extent of esophagectomy and gastrectomy, the extent of lymphadenectomy, and the tumor staging.