According to the connotation of sustainable development,the assessment of regional sustainable development should focus on the two aspects:“development” and “sustainability” of the regional development system(i.e.the regional social-economic-natural complex ecosystem,SENCE).So,some key concepts should be defined.These are development location(i.e.co-ecological location,L),development potential(i.e.co-ecological potential,P),and harmonious degree(H).Therefore,the degree of sustainable development(D)can be de...