Abstract: To conduct a dynamic simulation analysis on the loss of agricultural land in the process of urban agglomeration development is conducive to summarize the trend and mechanism of the agricultural land loss accurately, and provide basis for the formulation of agricultural land conservation planning. Taking Changsha, Zhuzhou,Xiangtan urban agglomeration as an example, through the collection and processing of remote sensing images and the establishment of spatial database, the grid system, the 12 directions rose map and the 3D hill diagram, this paper conducted a dynamic simulation analysis on the processes of the expansion of urban agglomeration and the loss of agricultural land. Through the centrifugal model, the driving mechanism of the loss of agricultural land was concluded. Then we carried out a prediction on the loss of agricultural land in 2020 and 2025. The results show that: the expansion of urban builtup area is the main reason of the loss of agricultural land in Changsha, Zhuzhou, Xiangtan urban agglomeration. Along with the evolution of urban agglomeration spatial structure, the loss of agricultural land has experienced a process of Centers Leading Centers and Industrial Parks Co leading Continuous Loss. If not effectively controlled, until 2025, a continuously distributed mega metropolitan area with acreage of 1 500 km2 will form. Meanwhile, the agricultural land between existing urban centers and industrial parks will gradually disappear, resulting in irreparable environmental damage. The key of agricultural land protection includes two aspects: on the one hand, the spatial structure and development mode of urban agglomeration should be optimized by spatial planning, on the other hand, the occupation should be controlled strictly in terms of policies and regulations. The research of this paper could provide a methodological reference for the formulation of environmental protection planning for the urban agglomerations in China.