Although green economy seems to emphasize the interaction between ecological environment and social economy, the content and the definition of green economy have not reached a consensus. In order to clarify the contents and the scope of green economy, the study reviews the relevant studies to have a better understanding of the definition of green economy and to check the relevant indicators in depth. Taiwan was ranked the 145th out of 146 countries based on the Environmental Sustainable Indicator (ESI), compiled by World Economic Forum (WEF). The main reason for the low ranking attributes to: first, many indicators take per square of environmental loading as the measurement unit, which causes unfavorable circumstances for small and narrow areas with high population density such as Taiwan; second, the indicator such as International Participation is also a constraint to Taiwan, for Taiwan is excluded by international communities due to the Chinese obstacle; third, lots of incorrect information about Taiwan has been cited. Corrected by some scholars, the ranking of Taiwan should be promoted to 120, slightly better than South Korea.
By using Principle Component Analysis to reanalyze the relevant information and Regression Analysis to verifying the related evidences, it is found the relationship between World Competitiveness Indicator, by IMD (Institute of Management Development), and ESI by WEF. The result shows that the other 20 countries are located around regression line, Taiwan excluded, by which it means Taiwan is the outlier among these 20 countries. In other words, if Taiwan is barred from the test, the regression analysis of the 20 countries indicates that the explanation ability of the model (R square value) rises from 0.059 (Taiwan included) to 0.382 (Taiwan excluded) and the slope also varies from 0.30 to 0.47. According to the above analyses, there is a positive correlation between ESI, by WEF, and World Compositeness Indicator by IMD. However, the ES