It is important to assess and monitor the level of regional sustainable development. With the development of observation and computer technology， scholars and stakeholders have realized that constructing an index is a critical step in evaluating the level of regional sustainable development. This paper introduced the "Sustainable Society Index" （SSI） from three perspectives， namely， theory， indicators framework， and methodology. This paper reviewed the literatures about the SSI based on two views， that is， limitation and improvement. There are three conclusions. First， the scholars and stakeholders widely thought SSI was a comprehensive method for assessing and monitoring the level of national sustainable development. Second， the limitations of SSI were mainly about the selection and aggregation of indicators. Third， the improvements of SSI were mainly about the aggregation methods. Finally， this paper also suggested possible research directions in the future.