On the background of coordinated development of Beijing-Tianjin-Hebei，this article constructs the theoretical framework of Beijing-Tianjin-Hebei ecological conservation area to expound its scope，function and the relationship between function and development.Based on the field research of Beijing-Tianjin-Hebei northwest ecological conservation area，which core areas are Zhangjiakou and Chengde，this paper studies the situation of coordinated development of ecological conservation area that undertakes the ecological security function in Beijing-Tianjin-Hebei，analyzes the problems，and puts forward the thoughts of development on several aspects，such as improving the system，reaching consensuses and innovating mechanism.