Abstract: Located at the middle of the Great Wall of the Ming Dynasty,the Great Wall of the Ming Dynasty in Ordos Plateau was an important component of frontier defense system in the Ming Dynasty. Therefore,the study of its scientific value is the basis for cognizing and protecting the Great Wall. Through a lot of field surveys of areas along the Great Wall of Ming Dynasty in Ordos Plateau,the paper proposed that as Ordos Plateau was short of geographic indications such as mountains and rivers,the Great Wall of Ming Dynasty became an important geographic indication after its formation. So,acting as a geographical boundary,it is of great significance in terms of geomorphology,climate,and agricultural and pastoral production.(1)The Great Wall of the Ming Dynasty is a geomorphological boundary between Ordos Plateau and Loess Plateau. The north side of the Great Wall of Ming Dynasty features high plains with highlands and lowlands as well as broad deserts,where wind action is the major exogenetic force; while the south side of the Great Wall of Ming Dynasty features the loess landform which consists of hills and gullies,where water erosion is frequent.(2)As the Great Wall of Ming Dynasty is located at the marginal area of summer monsoon in China,its south side is monsoon region,while its north side is non-monsoon region; in terms of temperature,its south side is in warm temperate zone,while its north side is in mid-temperate zone; and in terms of humidity,its south side is in semi-humid region,while in north side is in semi-arid or arid region. Therefore,the Great Wall of the Ming Dynasty is of geographical significance as a climatic boundary.(3)The Great Wall of the Ming Dynasty in Ordos Plateau is located at the central axis of the middle of China's agricultural and pastoral crisscross area. After the Great Wall of the Ming Dynasty was constructed, it became the boundary that divides China's agriculture and animal husbandry. Agricultural production models and land use in its two sides are obviously different. Its north side owns China's important pastoral areas and husbandry production zones,while its south side has been China's important dry-farming area since Qin and Han Dynasties. Therefore,the Great Wall of the Ming Dynasty is of geographical significance as an agricultural and pastoral boundary. The paper analyzed the significance of Great Wall of the Ming Dynasty in Ordos Plateau as geographical boundary from the perspective of regional differentiation. So,it is of practical significance in terms of discovering the scientific value of the Great Wall of the Ming Dynasty and facilitating heritage protection of the GreatWall.

Key words: the GreatWall, Ordos Plateau, geographical boundary