Abstract: China is the country with the largest amounts of high earth and rockfill dams in the world. Complex construction conditions and severe operation environment lead to great technical challenges in their construction and long-term safety guarantee. The main research results of the National Research and Development Program of China during the 13th Five-Year Plan period "Key technologies for construction and long-term safety protection of extra-high earth-rock dams under complex conditions" are introduced as follows: the mechanism of particle breakage on deformation of dams, flow rules during loading and creeping of rockfill materials as well as the damage process of in-situ structures of overburden soils are revealed, and the constitutive theories that can be used to predict the deformation developing process and distribution of dam body and foundation are established accordingly. The numerical methods for complex contacting problems and initiation and development of 3D cracks in high earth and rockfill dams are developed based on the computational contact mechanics. The practical consolidation theory of unsaturated soils is developed to simulate the deformation-seepage coupling effects during the whole life spans of high earth and rockfill dams. A new thermo-mechanical coupled method is proposed to account for the temperature-induced stress and damage of concrete slabs in concrete-faced rockfill dams. A high performance software platform is established to simulate the whole process including dam filling, impoundment and operation of high earth and rockfill dams. A series of techniques and measures preventing and controlling the deformation-induced damage processes are suggested for extra high earth and rockfill dams under complex conditions.