Ecosystem is essential for human survival and development. Yet in the economic-social-environment nexus, there is currently no widely used index to measure sustainability of the natural environment. The economic system has gross domestic product (GDP) to measure its performance, whereas social development has the human development index (HDI). The creation of a new ecosystem service evaluation system to account for ecosystem goods and services at national or regional scales has become a hot global topic for advancing the sustainable development agenda. Gross ecosystem product (GEP) is proposed as a comprehensive index for measuring the contribution of ecosystems to human welfare and socioeconomic development. GEP refers to the total value of final ecosystem goods and services supplied to people in a given region (like country, province, or county) annually. GEP accounting is piloted by several local governments in the PRC.