With the advancement of the “Grand Science Popularization(SciPop)”framework and the transformation of the digital media environment, SciPop in China is shifting from an expert-led, one-way knowledge dissemination toward a more interactive and multi-actor collaborative configuration. In this context, research on SciPop has moved beyond a focus on communication processes and effects to the systematic analysis of depper issues, including knowledge construction, communication structure, and trust formation. Drawing on the sociology of knowledge, social network theory, risk society theory, and cultural sociology, the study reviews the historical evolution of science popularization research in China and identifies three structural constraints: the shift of scientific trust from a single authority-based reliance to interactions among multiple actors; the imbalance between basic science and frontier technologies in knowledge supply; and the lag in disciplinary development and institutional support. On this basis, the study analyzes the coupling relationships and transmission mechanisms among these factors, revealing the underlying mechanisms that constrain the effectiveness of SciPop, and provides a theoretical reference for understanding the operational logic of science popularization under the “Grand SciPop” framework and for optimizing its institutional arrangements.