Since the 21st century, human development has faced severe challenges of economic, social and ecological issues, which arouses widespread attention on a series of new development concepts of green economy, green growth, and green development. The core connotations of the three green concepts revolve around how to achieve the coordinated development of economy, society and ecology. Because the three concepts are proposed under different temporal and spatial backgrounds and target countries or regions at different development stages, the interpretations of the three concepts are complicated and diverse, and have not reached a unified view.

Therefore, based on the theoretical framework of complex system, this study takes the definitions of the concepts of green economy, green growth and green development from SCI and SSCI journals and international organizations as the research object, and employs the machine learning method to explore the connotation and development concept differences of the three concepts by comparing and analyzing their core elements and feedback relationships. The results show that, from the perspective of the core elements of the human development system, the text frequency characteristics of green economy, green growth and green development indicate that the three concepts have similar core elements in the economic, social and ecological subsystems. They differ in their focus, where the green economy stresses social equity, green growth pays more attention to employment and technical issues in economic development, and green development emphasizes industrial issues in economic development. From the perspective of the feedback relationships in the human development system, the commonality of the three concepts lies in the shared cognition that the positive feedback structure of economic growth is the basis of the system, where economic development contributes to social progress and inclusiveness, and social harmony thereby promotes economic development. Furthermore, the ecological environment acts as both material basis and restrictive factor of social and economic development, which constitutes a negative feedback structure. The differences in the feedback relationships of the three concepts are reflected in the differences in their key feedback structures. For example, green economy focuses on preventing financial risks, while green growth and green development emphasize industrial structure adjustment and employment increase.

The main contributions of this study can be divided into three aspects: （1） This study explores and analyzes the core connotations and differences of the concepts of green economy, green growth and green development from the complex system perspective, rendering a more scientific explanation of development issues from the theoretical level and providing reference for the theoretical innovation and practice of the development concepts. （2） The adoption of machine learning method in the study achieves a more comprehensive recognition and comparison of the implicit connotation and feedback relationships of the concepts based on the in-depth exploration of the meaning and relationship of the words, which is a beneficial supplement to existing mapping knowledge domain analysis. （3） Based on the analysis of the connotation of the three concepts, this study puts forward the following three potential directions for future research: First, for theoretical innovation, future research should identify and recognize the elements and the feedback relationships of the human development system more scientifically and accurately to promote the expansion and evolution of the development concepts. Second, regarding research paradigms and methods, the improvement of development concepts requires the continuous updating and integration of research paradigms and methods. Thus, future research should realize the expansion and scientization of the theories by adopting complex system paradigms and multidisciplinary methods. Third, concerning the research context, future research should focus on the research and practice of green development theory in China’s special context and actively explore green development paths with Chinese characteristics, so as to provide theoretical and practical reference for China’s realization of green transformation.