Abstract: The landform-climate-vegetation patterns of forest-steppe ecotone on the southeast of Inner Mongolia Plateau were revealed and the result showed that vegetation distribution was affected by the combination of climate and landform. Regionally, forest community type changed along precipitation gradient from reletively humid areas to arid areas as birch, oak and popular forest, and needle leaved forest was distributed closer to forest drought limit. Locally, broad-leaved forest was distributed mostly on shady slope where evaporation was weak and soil bulk density was low and steppe on sunny slope with strong evaporation. Elm woodland was distributed on sandy land with weak capillary force and little evaporation. Based on these results, we pointed out that first, regionally when choosing tree species, their individualistic precipitation limitation should be in primary consideration; second, in microzone with the range of appropriate precipitation, considering the effects of slope aspect on soil water condition, forest should be nourished on shady slope with an angle of 10 to 40 degree; third, local species, forest density and combination of tree, shrub and grass must be taken into account on both regional and local scale, and it is inappropriate to grow dense forest on sandy land.