Against the background of financial globalization and a significant increase in uncertainty, studying the impact of global economic policy uncertainty on the abnormal flows of international capital and exploring the regulatory effect of financial openness in it are of great practical significance. However, existing literature mainly focuses on the direct impact of global economic policy uncertainty on abnormal flows of international capital, or the effect of financial openness on such flows, overlooking the moderating role of financial openness in the impact of global economic policy uncertainty on abnormal flows of international capital. The article employs the IMF database and draws on the method of calculating abnormal international capital flows from Forbes & Warnock (2012), categorizing them into four types: flight, retrenchment, surge, and stop. The frequencies of flight, retrenchment, surge and stop events for 49 economies are calculated, and a Probit model is constructed to investigate the impact of global economic policy uncertainty on abnormal flows of international capital and its heterogeneity. Furthermore, the moderating role of financial openness is explored. The empirical study finds that: when global economic policy uncertainty rises, the events of capital flight and surge decrease significantly, and the events of capital retrenchment and stop increase significantly; the impact of global economic policy uncertainty on capital surge in emerging and developing economies is smaller than that in developed economies, and the impact of global economic policy uncertainty on capital flight in emerging and developing economies is larger than that in developed economies; global economic policy uncertainty affects the abnormal flows of international capital mainly through affecting other investments; the level of financial openness rises, and the impact on international capital flows is more heterogeneous than that in developed economies; an increase in the level of financial openness strengthens the negative impact of global economic policy uncertainty on capital flight and surges. Compared with previous literature, this paper expands in three aspects: firstly, it studies the impact of global economic policy uncertainty on abnormal flows of international capital from the perspective of financial openness, enriching the research perspective on the relationship between global economic policy uncertainty and abnormal flows of international capital; secondly, it systematically investigates the impact of global economic policy uncertainty on abnormal flows of international capital from the perspectives of national heterogeneity and capital type heterogeneity, enriching the empirical evidence of this research; thirdly, through marginal effect function analysis, it is found that the level of financial openness plays a moderating role in the impact of global economic policy uncertainty on abnormal flows of international capital, providing decision-making references for preventing and resolving the impact of global economic policy uncertainty. The research in this paper reveals, to a certain extent, the internal logic of global economic policy uncertainty and abnormal international capital flows, which can provide a reference for the government to formulate policies for preventing and resolving the risk of abnormal international capital flows against the background of rising global economic policy uncertainty and the promotion of a high level of financial openness.