Abstract: Exterior window is an important room transformation medium for residential building between indoor and outdoor environment，and it is also the key link for building energy-efficiency． Based on the field investigation and statistics data of building exterior windows in local market and existing residential buildings，window’s problems and basic physical and thermal properties were analyzed． Then，key design techniques for new kind energy-saving exterior window were summarized． The paper pointed out it would achieved the purpose of lowing building energy-consumption and reducing green house gas emission，only in popularizing the energy-saving window optimally designed based on local architecture culture and climate characteristics．