Under intensifying competition with China,the United States is trying to co-opt its Asia-Pacific allies to contain China.Recently,some US Asia-Pacific allies have adjusted their policies towards China and the US,which is closely related to their domestic political changes.Existing studies have explored the influence of domestic politics on alliance politics from the perspectives of ruling party preference,regime legitimacy,domestic crisis and audi-ence cost.The cases of Australia,the Philippines and South Korea indicate that competition among political parties makes alliance policies partisan,political survival crises of leaders strengthen their willingness to adjust alliance relationships,while anti-China sentiment in the countries hinders them from developing bilateral relations with China.The adjustments of the Asia-Pacific allies'policies towards China and the US are driven by domestic politics,while leading to more political challenges to their governments and dynamics of the regional situa-tion.China should pay attention to improve the public's favorability towards itself in Asia-Pacific countries,deepen economic and trade cooperation with the countries,enhance stability of regional multilateral security mechanisms,thereby properly respond to the adjustments of the US Asia-Pacific allies'policies.