[Objective] Ecological land plays an important role in maintaining ecological balance and supporting economic development. It is of great practical significance to study the spatio-temporal evolution characteristics and driving mechanism of ecological land use in central Yunnan urban agglomeration to optimize the ecological security pattern, promote the construction of ecological civilization in Yunnan, and build a strong ecological security barrier in southwest China. [Methods] Based on the identification of ecological land use in the central Yunnan urban agglomeration from 1990 to 2020 by Google Earth Engine (GEE) cloud platform, the spatial and temporal change trajectory and driving mechanism of ecological land use in the central Yunnan urban agglomeration were explored by using change trajectory analysis, hot spot analysis and geographic detector. [Results] (1) The change of ecological land in the central Yunnan urban agglomeration mainly occurred in the transition zone between non-ecological land and forest land, and the change between ecological land (forest land and grassland) mainly occurred in the mountainous area in the north and south of the study area. (2) The changes of ecological land use are mainly less of high frequency and low frequency, and the frequency changes show obvious aggregation effect in the hot and dry valley of Yuanjiang River, the hot and dry valley of Jinsha River and the karst zone of East and southeast Yunnan; (3) The influence of social and economic factors on ecological land use is significantly higher than that of natural factors. Driven by natural environment, cultivated land expansion and ecological restoration policies, the interaction of multiple factors has more explanatory power on ecological land use change. [Conclusion] The ecological land in the urban agglomeration of central Yunnan Province is broken, the change of natural environment and the increasing human activities can easily lead to the change of ecological land, and it is urgent to formulate reasonable ecological protection measures by region to build a strong ecological security barrier in southwest China.