Objective This study aims to systematically review and compare the funding structures, research themes, and developmental trends of health-related implementation science projects funded by the National Natural Science Foundation of China (NSFC) and the United States National Institutes of Health (NIH). The findings will offer valuable insights for optimizing the strategic planning and funding policies of health-related scientific research in China.

Methods With "implementation science" and "implementation research" as core keywords, relevant data on health-related implementation science funding projects from both NSFC and NIH were retrieved and screened from their official websites and various commercial databases, covering the period from January 1, 2000 to December 1, 2024. CiteSpace 6.1.2 R6 was then employed to conduct visualized analyses of theme clustering and temporal trends, enabling a comparative analysis of the funding structures, research themes, and developmental trends of these projects between China and the United States.

Results A total of 39 NSFC-funded projects and 487 NIH-funded projects were included in the final analysis. Both China and the United States demonstrated a strong commitment to the strategic value of implementation science in transforming public health policies and healthcare delivery systems, consistently increasing financial investment in this area. However, significant differences were observed in their funding priorities. China primarily focused on mental health and psychological well-being, whereas the United States emphasized addressing major national or international multi-center public health challenges and supporting large-scale collaborative network research. Regarding research collaboration networks, the implementation science projects funded by NSFC were concentrated at Sun Yat-sen University and Peking University, while in the United States, the University of Washington, Johns Hopkins University, and Yale University ranked highest. High-frequency keyword analysis of implementation science funding projects revealed that China′s research themes concentrated on "implementation science," "multiphase optimization strategy," "implementation research," "empirical research," "effect evaluation," "community," "elderly," and "children." The United States focused on "implementation science," "research personnel," "public health," "evidence base," "scale up," "implementation strategy," and "AIDS prevention," with denser distribution of keyword hotspots. Analysis of developmental trends indicated that China′s research hotspots were relatively dispersed across the time dimension, exhibiting short-term and discontinuous characteristics. Conversely, the United States′ research hotspots showed significant centrality, with greater continuity and regularity in their thematic evolution.

Conclusions Substantial disparities exist between China and the United States concerning the funding priorities, scale, and developmental trajectories of implementation science. China still needs to further strengthen its research mechanisms, inter-institutional collaboration, and methodological innovation in this domain.