As entrepreneurial activities become one of the most prevalent trends in the global business arena, research institutions around the world paid lots of attention on those activities, developed measurement indices to thoroughly understand those activities, and tried to utilize those indices to monitor as well as enhance the soundness of entrepreneurial environment. Based on the criteria of academic value and social influence, five index systems were selected for further investigation and thorough comparison, including: Global Entrepreneurship Monitor (GEM) developed by Babson College, Global Entrepreneurship and Development Index (GEDI) proposed by Prof. Zoltan J. Acs, World Competitiveness Yearbook (WCY) published by International Institute for Management Development, Doing Business Report conducted by the World Bank, and Innovation Union Scoreboard (IUS) initiated by the European Union. In spite of the lack of a comprehensive comparison and integrated discussion, rankings from those measurement indices were extensively used for investigating, evaluating, and adjusting entrepreneurial policies in different countries; therefore, it is quite common for government agencies to lose their focuses, mistakenly cite the reports, or erroneously interpret the results. The purpose of this study is to review the aforementioned measurement indices and inspect the suitableness of them. Results derived from study are: in addition to the differences on the purposes of these measurement indices, more discrepancies could be found in the definitions of terms, the level of analysis, the process of conducting the investigation, and the time period used for collecting data. Secondly, although it is quite common to think of entrepreneurial activities as the demonstrations of national competitiveness, innovative capability, or the business environment, the rationality of the linkages and the rigorousness of the methods used for connecting different concepts are unconvinced; thirdly, the advances of Taiwan from the rankings of different measurement indices suggest that the climate and the entrepreneurial environment are very prominent; finally, conducting research on entrepreneurial activities and constructing databases for storing relevant data are not only essential for developing international entrepreneurial indices but also vital for researchers as well as practitioners to be geared to international research communities.