The Eighth International Symposium on Permafrost Engineering was held in Xi’an, China, October 2009. The major topics discussed in the symposium included: permafrost engineering (involving design, construction and evaluation); mitigation of frost hazards in the regions affected by seasonally frozen ground; properties of frozen soils, model development and their applications; frost hazards and periglacial environments in mountain and plateau regions; climatic, environmental and cryospheric changes; and permafrost hydrology, cold regions water resources and land uses. The papers submitted to the symposium and lectures during the meeting represented some new developments of research on cold region engineering and environment. Here we summarized the works of the symposium in topics including: Permafrost engineering; General geocryology; Properties of frozen soils: model development and their applications; And climatic, environmental and cryospheric changes. During the symposium, the attendees pointed out that future studies should pay more attention to theoretical study and engineering mechanism study, and also on interaction between climate change and cold region environments and their engineering affects.