The international coordination of macroprudential policies serves as a crucial instrument for effectively safeguarding financial stability and appropriately mitigating external containment amidst advancing financial integration and liberalisation. Although the International Monetary Fund (IMF) and the Bank for International Settlements (BIS) have consistently urged countries in recent years to coordinate their use of macroprudential policies to uphold the global capital order and financial stability, regulatory authorities, anchored by domestic financial stability objectives, frequently exhibit a preference for independent prudential management. This tendency has resulted in a prolonged deficiency in discussions concerning the macroprudential dimension within the design of international coordination mechanisms. Against the backdrop of a century-defining transformation, the checks, balances and rivalry among various national macroprudential policies are growing increasingly complex. The spillover of macroprudential policies from developed countries, which is characterised by risk transference and regulatory arbitrage, has once again laid bare the latent hegemonic features within international coordination processes. Consequently, the majority of emerging market countries are left to passively absorb coordination outcomes predominantly shaped by developed countries. There is thus a pressing need for the international community to establish a timely and effective framework for such coordination that gives full consideration to the interests of numerous emerging markets, with China as a prominent representative.To investigate this critical gap, this paper first constructs a two-country macroprudential policy game model incorporating an exogenous shock parameter to analyse the impact mechanism of international macroprudential policy coordination on financial stability. It subsequently employs a conditional dynamic spillover index framework and a "semi-structured" data combination strategy to identify the dynamic evolution of this coordination. Finally, building upon a mixed-frequency measurement of the financial stability index, it examines the non-linear effects of macroprudential policy coordination on China's financial stability.The analysis yields three principal findings. First, a relationship of strategic substitutes exists between the two countries' macroprudential policies. Although regulatory cooperation under homogeneous conditions is more conducive to safeguarding financial stability, the fundamental disparities in their macro-financial environments render non-cooperation the more likely predominant form of international coordination. Second, international macroprudential policy coordination is closely associated with major global economic and financial events. The coordination of China's macroprudential policies with other countries demonstrates characteristics of asynchronicity and asymmetry, and the level of policy coordination with emerging market countries is higher. Third, when China's financial stability is at a lower quantile, coordination with developed countries enhances the shock resilience of its financial system. Conversely, when financial stability is relatively robust, coordination with emerging market countries is more effective in promoting it. Collectively, this research confirms the necessity of a systematic analysis of the financial stability effects arising from international macroprudential policy coordination and yields insights for how China might enhance the efficacy and sustainability of its regulatory targeting and policy stance adjustments within such international coordination frameworks.