Abstract: Based on the structural features of the cold-formed thin-walled steel structure residence，a energy saving environmentally friendly double-layer air circulation system with the respiratory function was developed，and Fluent ＆ Airpak softwores were used to do 3D sumulation to explore the impact mechanism of the system on indoor thermal environment． It was examined various index properties and influencing factors including velocity field，temperature field，PPD-PMV distribution etc，from the various components of the air circulation system during operation Fluent and Airpak，have been examined，whereby to evaluate the indoor airflow and air quality．Research shows that the buffer layer of air can provide good air source for both the inner and outer air layer; the outer layer of air can dynamically isolate indoor and outdoor heat by taking advantage of stack effect; Under the premise of low energy consumption，the utilization of the entire double air circulation system can improve the indoor thermal environment as well as provide 24 － hour fresh air for the indoor occupants，so that the purpose of energy saving and environmental protection could be achieved．