Abstract: This paper introduced the definition and characteristics of adaptive security framework. Combined with the requirements of railway information system network security under the new situation, from four aspects of infrastructure security, defense in depth, active defense, joint defense and joint governance, the paper proposed the design idea of railway network security framework based on adaptive security, and formed four key research directions of risk in-depth security defense, data in-depth security detection, automatic rapid response and security information early warning around the framework. Through the systematic construction mode, it can be improved the adaptive ability of railway network security defense.