<p>The intensification of China-U.S. tensions has led the U.S. to impose sanctions on selected Chinese universities. These measures have affected both the willingness and opportunities for academic collaboration between U.S. and Chinese scholars, raising concerns about the healthy development of global scientific cooperation. This study aims to quantify the actual impact of U.S. sanctions on Chinese universities and identify the research domains where China–U.S. collaboration has declined the most. Drawing on more than 290,000 collaborative publications across 45 universities from January 1, 2016, to December 31, 2023, this study employs a Generalized Random Forest model with counterfactual estimation to assess the effects of U.S. sanctions on targeted universities. Research findings indicate that U.S. sanctions on Chinese universities precipitated the loss of over 3,700 potential collaborations, accounting for 22.41% of sanctioned institutions’ collaborations with U.S. counterparts. The negative repercussions were especially pronounced at top-tier universities. Strategic domains–including vaccine development, quantum chips, and remote sensing technologies-experienced the largest disruptions because of their alignment with national security priorities and technological competition, whereas the social science registered minimal effects. Projections suggest that, if bilateral relations continue to deteriorate, China–U.S. co-authored research articles could decline by an additional 10% over the next six years; conversely, improvements in relations could enable a recovery of up to 4%. Overall, this study reveals the significant impact of fluctuations in international relations on global scientific collaboration and introduces a novel empirical framework integrating machine learning and causal inference into educational research.</p>