The composition and spatial changes of the ecosystems in the Lugu Lake Scenic Area from 1990 to 2015 were analyzed in this study. With the goal of providing a scientific and theoretical basis for ecological and environmental planning in the Lugu lake area, we used the classification and extraction of ecosystem information method and landscape index method to explore the ecosystem spatial changes and their pattern by integrating remote sensing with GIS technology. Furthermore, we analyzed the driving forces behind those changes. During this 25-year period, the main type of ecosystems in the Lugu Lake scenic area could be divided into five types, including farmland ecosystem, forest ecosystem, grassland ecosystem, water ecosystem, and human settlement system. From 1990 to 2005, the conversion between farmland, forest, and grassland ecosystems occurred. However, from 2005 to 2015, extensive areas of forest, grassland, and water ecosystems changed to farmland and human settlement systems. Landscape fragmentation and the complex degree declined, whereas connectivity and integrality of the scenic area was gradually enhanced. However, there was a larger difference between the proportion of each ecosystem type. Policy guidance was the main driving force for the farmland ecosystem. The Returning Farmland to Forest and Grass Project and human activities were the main driving forces for the forest and grassland ecosystems. Wetland afforestation and human activities were the main driving forces for water ecosystem. The increasing demand for human settlements was the main driving force for the human settlement systems. Finally, several planning suggestions were proposed to solve the existing problems in the Lugu lake ecosystems.