Based on the measurement of internalizing geographical elements, the paper quantitatively evaluates the competence of region (system) sustainable development. And the paper also denotes the competence of region (system) sustainable development by the balanced result of the various effects (the positive is competence, and the negative is cost) on suitable development produced by geographical elements. Taking Ecotone of the west of Jilin Province as study object, the paper insists that the cost of suitable development is maily the cost of estoration of damaged ecosystem in the present stage, and the paper finishes the cost accounting. The research shows that the regional distribution of cost is not obvious, while is characterized with accumulated magnification along with time. So it is necessary to govern the cost timely. In the end, some advices on the restoration to grassland, fostering of grassland and cost overflow are proposed.