It is my great honor to welcome you to the 7th CAS-TWAS Symposium on Green Technology  (GT2018), which will be held in Beijing, China on July 22-25, 2018. The CAS-TWAS symposium has been successfully held six times since 2012, aiming to provide a high level platform for academic exchange and project cooperation worldwide, especially for developing countries. The symposium focuses on a wide range of topics including mineral and renewable resources, clean energy, bioengineering, new materials, environment, and other related topics.