At present, the circular economy is emerging as a strategy for sustainable development. What is important in promoting the circular economy is to assess its current level and take measures for assessment. This paper discusses some methodological issues in comparing and assessing the efforts for the circular economy at the international level. To this end, the authors explain the theoretical premise related to the assessment of efforts for the circular economy, establish an indicator system for assessing the efforts for the circular economy, and suggest a method for comprehensively assessing the efforts for the circular economy by country. The conclusions are that (a) the comparative evaluation of activities related to the circular economy by country requires a unified standard or category that can cover these activities, including all factors that meet sustainable development; the outcome, process, and guarantee of the circular economy, and this can be the circular economy effort and (b) the circular economy effort of a given country must synthetically be assessed by using the indicators capable of showing all aspects. These conclusions may contribute to establishing a new theoretical foundation that can include various aspects of the circular economy activities and to setting a practical and methodological foundation for evaluating each country’s various activities related to the circular economy at the international level and can serve as a policy basis for identifying the weak and strong aspects of circular economy activities at the domestic or international level and establishing technological and economic measures to strengthen the weak aspects.