The Chinese government has proposed a synchronous development strategy for new urbanization, industrialization, informatization, and agricultural modernization (called ''New Four Modernization,'' NFM), which provides new ideas for solving social sustainable development problems such as large urbanrural gaps, irrational industrial structures, and environmental pollution. This study aims to examine their interactive modes and provide a theoretical basis and empirical evidence for the synchronous development of NFM. The analysis started with the interaction mechanisms of new urbanization, industrialization, informatization, and agricultural modernization. Principal component analysis (PCA) was used to comprehensively evaluate the level of NFM development. A vector auto-regression (VAR) model was constructed to analyze the interaction effect empirically. The findings were as follows: (1) China's new urbanization, industrialization, informatization, and agricultural modernization development levels were rising, and there was a long-term equilibrium relationship between them. (2) The Granger joint test found that the combined effects of any three developments in new urbanization, industrialization, informatization and agricultural modernization have a significant causal relationship with the development of the other, which showed that the synchronous development of NFM had an inherent motivation. (3) New urbanization occurred at the core of NFM interaction mode and was the main driving force for the development of the other three modernizations. Lastly, this study provides a new case for better understanding the interaction mode of NFM in emerging countries such as China, and provides Chinese experience for developing countries.INDEX TERMS New four modernization, sustainable social development, interactive mode, principal component analysis (PCA), vector auto-regression model (VAR). BRIAN TEO SHENG XIAN received the B.Sc. (Hons.) and Ph.D. degrees from University Putra Malaysia (UPM), Malaysia, in 2008 and 2014, respectively. He is currently an Associate Professor with Management & Science University (MSU), where he is also heading the International Academic Affairs Department. His years of experience in multi-disciplinary research in both business and scientific world have garnered his unique areas of expertise. His research interests include the spectrum of areas, including data mining, data analytics, causal reasoning, the scientific understanding of learning, data visualization, medical tourism, strategic management, complementary and alternative medicine, cosmeceuticals and skin care, and colloidal science.