Abstract: Beijing-Tianjin-Hebei Mountainous Area is limited by geographical conditions, and has prominent problems in regional towns development and disaster prevention and control. Starting from the relationship between mountain towns expansion and ecological constraints, this paper clarified the driving force of mountain towns expansion and the typical disaster characteristics of mountainous area under the influence of urbanization. This paper constructed the ecological security pattern of Beijing-Tianjin-Hebei mountainous area with the P-S-R model based on the prevention and control of mountain torrent disasters. Coupling the expansion pressure strength of each town, four types of expansion patterns of mountain towns under ecological constraints were obtained: Low expansion + low ecological security level, moderate expansion + low ecological security level, high expansion + average ecological security level, low expansion + high ecological security level. Therefore, through the eco-oriented sustainable urbanization development strategy and the construction of regional ecological network under national land use and spatial plan, resilient safety development paths of mountain towns were proposed, so as to effectively reduce the risk of mountain torrent disasters and ecological stress of mountain towns expansion.