Danjiangkou City is the core water source area of the South-to-North Water Diversion Middle Route Project. This paper provides scientific support for the ecological safety of Danjiangkou Reservoir Area by conducting research on dynamic changes of land use, landscape pattern and ecosystem service value. Based on the remote sensing image data of Danjiangkou City from 2003 to 2018 and software such as ENVI 5.3, ArcGIS 10.5 and Fragstats 4.2, the dynamic changes of land use in Danjiangkou City were counted, the landscape pattern change index was analyzed, and the ecosystem service value was measured. The results show that the land use types in Danjiangkou City have significantly changed. The area of water, woodland, and urbanized land respectively increased by 38.07%, 19.73%, and 11.63%, the area of cropland land and orangery land decreased by 42.83% and 52.40% respectively. Except in 2003, the land use degree was as high as 25.02%, and the remaining years remained at about 23%; The landscape spatial pattern has changed significantly. The patch types within the city area tend to be distributed in a regular and balanced trend, the patch types have formed a good connection, the degree of landscape aggregation is gradually increasing, and the spatial distribution tends to be concentrated. The value of ecosystem services in Danjiangkou City has continued to grow, from 105.31×10⁸ yuan in 2003 to 116.99×10⁸ yuan in 2018. Among them, water conservation and soil formation and protection have the highest ecological value, and raw material production, aesthetic landscape and food production account for a relatively low proportion. In the future urban construction, we should increase the protection of waters and woodlands, optimize and adjust the land use structure, rationally plan construction land, develop pollution-free agricultural production, add natural landscapes in time, and steadily increase the value of regional ecosystem services.