3.1　Build DPSIR Model

DPSIR model,a universally accepted model,is widely used in the evaluation of sustainable development of the earth,countries and regions.It defines the evaluation indicators of a natural system as Driving forces,Pressure,State,Impact,Responses,and each type contains a number of indexes.In this paper,DPSIR model,for evaluating the sustainability of a country,can be established as shown in Figure 1.

Figure 1　The overall block diagram of DPSIR model

The selection of indicators for each stage is very important and it will directly affect the results of our evaluation.We choose the important factors acknowledged in the United Nations Conference as evaluation factors.