With a primary consideration of the ecosystem service function of different grassland types, and basing on the principles of regional planning, methodology, nomenclature, the features of regional eco-environment, as well as “3S” techniques, The grassland and agro-pastoral transitional zone in northern China was classified into 3 ecological regions and 10 eco-function regions. Then, the elaborations were carried out in detail regarding the territory of each function region, primary eco-environment issues, core ecological service functions and means to be adopted for protection and sustainable development of each specific function region. We believe that the developed regionalization result is very helpful in understanding the ecological service function value of different grassland types, facilitating effective use of grassland resources, promoting optimal layout of agricultural production，improving the regional ecological security, as well as strengthening the regional sustainable development in the grassland and agro-pastoral transitional zone of northern China.