Abstract: Take Fuliang County of Jiangxi Province as the research area.Based on land use data and social and economic data, the evaluation system is constructed from three aspects: natural conditions, human activities and landscape pattern.The spatial and temporal differentiation of land ecological security in Fuliang County from 2000 to 2018 is studied by using the CRITIC-TOPSIS model.The obstacle degree model is used to analyze the main obstacle factors affecting the land ecological security in Fuliang County. The research results show that:(1) From 2000 to 2018, the land ecological security level in Fuliang County showed a small decline, and experienced a process from good to worse and then to better.(2) There are significant differences in the land ecological security conditions among towns in Fuliang County, and the reasons for the differences are also different.The relatively good areas are mainly concentrated in the east and the central -northern part, while the poor towns show the characteristics of clustering around the county and urban areas. Jiaotan Town and Xianghu Town show their particularity.(3) The land ecological security state of Fuliang County is affected by various obstacles. At different time nodes, the obstacles and the degree of action are not the same, and the relationship is complex.Water network density, topographic location index, soil and water coordination index, per capita cultivated land area four obstacle factors to the land ecological security of Fuliang County is more prominent factors.