Since the reclamation in 1918, there has been almost 100 years of settlement building and agriculture developing in Bairin Left Banner of Inner Mongolia.Before the 1930s which is taken as a turning point, the distribution of the settlements there was charactered by spatial expanding, after that turning into density increasing.In the mean time, the elevation of the settlements also began to expand from the height of 400-600 m, where the natural condition is quite advantageous, to other areas.The distribution change of settlements shows that the environmental disturbance by human activity has been continuing strengthened since the 1930s.According to the connection between the settlements and the cultivated land, it is sure that the 23?10³ ha of cultivated land reclaimed in about 1933 were mostly in the area of 400-600m height, while another 50?10³ ha reclaimed in the succeeding several decades were mostly distributed in the area without good natural condition, some around the settlements of 400-600m height.Cultivated lands on different heights have brought on different environmental disturbance.Although the area of 400-600m height has the best natural condition within Bairin Left Banner and man-milieu relationship there is finely working, the ecological environment there is fragile.With the expanding of the settlement and the expanding of the cultivated land, distinct environmental problems come out.These problems become more severe in other areas with poorer natural conditions.Pushed by the population, the spatial variation and the environmental choice of Bairin Left Banner have gone a process of getting denser and worse.Hence there appeared the conflict of man-milieu relationship made by the expanding of the farm and the limit of the resources.