The existence of mountains-rivers-forests-farmlands-lakes-grasslands systems emphasizes the need for ecosystem integrity and reflects the relationships among natural ecosystems. Thus, ecological protection and restoration methods should be based on the system theory. This study focuses on the ecological protection and restoration of mountains-rivers-forests-farmlands-lakes-grasslands systems in specific regions. An ecological network allows the connection of fragmented habitats and aids the understanding of various elements of an ecosystem. Therefore, using the Zuoyoujiang River basin in Guangxi Province, China as an example, this study selected protected areas as ecological sources, analyzed the structure of potential ecological corridors and the importance of ecological sources using a combination of the minimum cumulative resistance and integral index of connectivity (IIC) models, and discussed the spatial distribution of potential mountains-rivers-forests-farmlands-lakes-grasslands ecological networks. A total of 69 potential ecological corridors were identified; however, there were no available corridors in the central part of the study area, which resulted in an obvious north-south barrier. Among the 51 source patches, only 3 patches had an IIC greater than 0.2, and the overall connectivity of the landscape was poor. Analysis of the corridor composition indicated that the proportion of cultivated land was 20.28%, second only to that of natural forest land (74.16%). Thus, cultivated land has a considerable effect on the construction of ecological networks. A total of 9 key ecological nodes and 23 breakpoints were selected through the superposition of corridors and roads, and corresponding restoration and optimization countermeasures were suggested. The results of this study provide insights into biodiversity conservation in the Zuoyoujiang River basin in Guangxi. Further, this study acts as a preliminary exploration for the ecological protection and restoration of mountains-rivers-forests-farmlands-lakes-grasslands ecosystems and will act as a reference for such studies in the future.