Abstract: Under the background of rapid urbanization, the intensity of human activities has continued to increase, which significantly changes the land-use pattern and ecological processes, and consequently causes series of ecological security issues, including habitat degradation, carbon storage decline, and intensified soil erosion. Taking Chengdu City as the study area, based on multi-source spatiotemporal data from 2000 to 2020, the spatial pattern, temporal evolution characteristics, and driving mechanisms of four key ecosystem services, including habitat quality, carbon storage, water yield, and soil conservation, were systematically analyzed by using InVEST model, XGBoost machine learning algorithm, SHAP-based explainable analysis method and indirect gradient analysis based on principal components. The results indicated that the overall ecosystem services in Chengdu were characterized by obvious spatial differentiation, in which habitat quality, carbon storage, and soil conservation were highly coupled in spatial distribution, and the high-value areas were mainly concentrated in the western mountainous regions, while low-value areas were predominantly distributed in the eastern plains and the central urban areas. In contrast, the spatial pattern of water yield was relatively fragmented, which was mainly controlled by precipitation conditions. The indirect gradient analysis revealed significant relationship between habitat quality, carbon storage, and soil conservation, whereas water yield generally showed trade-offs with these regulating ecosystem services. XGBoost-SHAP analysis further demonstrated that natural topographic factors (elevation and slope) were dominant in the four types of ecosystem services, and annual precipitation was the key controlling factor for water yield, while human activities indicators such as population density, GDP, and nighttime light intensity exert significant negative effects on habitat quality and carbon storage. These findings provide a scientific basis for revealing the synergy and trade-off relationship of ecosystem services and its nonlinear driving mechanisms under the background of rapid urbanization.