Abstract:The western China has developed the Earth’s unique ecosystems, which is not only the main provider of ecosystem products and the important barrier of ecological security in China, but also the key area of ecosystem protection and restoration because of its ecological fragility. In recent years, a series of the major protection and restoration projects of ecosystems have been implemented, and have achieved remarkable progress in western China. Nevertheless, due to its ecosystem instability and unsustainability, ecological security is still facing severe challenges in western China. This study first analyzes the crucial roles of the western region as an ecological security barrier in China, elucidates the characteristics and changes of its ecosystems, and assesses the progress of ecosystem protection and restoration. Then, the challenges and the trends are analyzed and the key tasks are proposed of science and technology development for ecosystem protection and restoration in the new era, which is expected to provide scientific and technological support for the ecological barrier building in the western China.