Abstract: Southwest China serves as a crucial ecological barrier in China, and the rational utilization and protection of its ecological land are of great significance for safeguarding national ecological security. Taking Chongqing, Sichuan, Guizhou, Yunnan, and Xizang as the study area, this paper integrates Landsat remote sensing images and multi-source socio-economic data, applies methods such as land use dynamic degree, transfer matrix, and standard deviation ellipse to analyze the spatiotemporal evolution characteristics of the landscape pattern of ecological land from 2000 to 2020, and constructs an Extreme Gradient Boosting-Shapley Additive exPlanations (XGBoost-SHAP) coupling model to quantitatively identify core driving factors and analyze the nonlinear relationships and interaction effects among them. The study reveals that the evolution of ecological land in Southwest China shows significant type and regional differentiation, with 2010 as an important inflection point; natural background factors act as the fundamental drivers of the evolution of ecological land patterns, the disturbance effect of socio-economic factors continues to increase, and the regulatory role of ecological protection factors becomes prominent in the later period; there are four types of interaction effects such as positive synergy and conditional dependence among driving factors, and the driving mechanism shifts from sole dominance of natural background factors to multi-factor synergy. The differentiated ecological land protection strategies proposed in this paper can provide scientific support for maintaining ecological security and formulating land use planning in Southwest China.