The Papilio xuthus is a widely distributed species in the genus Papilio of the family Papilionidae, possessing ecological, ornamental, and socio-economic service values. To determine the ecological role of P. xuthus and assess its population distribution under future climate change scenarios, this study utilized the MaxEnt model to predict the geographic distribution of P. xuthus in the future and evaluate its population dynamics. The results indicated that P. xuthus is currently widely distributed in East Asia, with a high suitability area of 1827.83 × 10³ km², primarily in China, Japan, North Korea, and South Korea. Climate change has a significant impact on the geographic distribution of P. xuthus, with its high suitability areas decreasing in the future, particularly within China, where the change is projected to be as high as 46.46% under the SSP126 scenario by the 2050s. The centroid of its high-suitability area is expected to shift northeastward. Key environmental variable analysis revealed that Temperature Seasonality, Mean Temperature of the Wettest Quarter, Precipitation of the Wettest Month, and Precipitation of the Warmest Quarter are critical factors influencing the selection of suitable habitats by P. xuthus. This study assessed the distribution of P. xuthus and provided conservation recommendations, offering a reference for future population control and conservation efforts.