The significance of a“balance sheet”in estimating the developmental sustainability of a specific region is expounded and a systematic analysis of the regional developmental sustainability is made from the perspective of the systematic branch of sustainability study. The paper also presents the fundamentals and methodologies for preparing a“balance sheet”for regional sustainability evaluation, and further designs the measurement methods for“assets”and“liabilities”in the balance sheet. The preparation of balance sheet provides a solid theoretical foundation for accurate judgement on the “development quality”of a particular region.