Basing on the climate and soil conditions in northwest plateau of Hebei Province, this study compared the actual productivities of different vegetation types. The results showed that the productivity of crop and grass was much higher than that of forest either on meadow chestnut soil or on sand chestnut soil, and the difference of productivities between crop and grass was small. As for different soil types, the productivity of grassland chestnut soil was higher than that of sand chestnut soil. According to the differences of productivities between crop, forest and grass, most farmland should be converted to grassland but not forest land. After farmland converted, the production structure should be adjusted in considering both the protection of ecological environment and the development of local economy.