Abstract: The evolution process of traditional rural settlements is affected by two mechanisms of ‘endogeneity’ and ‘exogeneity’, forming the ‘dual-structure’ of its spatial form. On the basis of combing the evolution process and dual-structure characteristics of coastal defense cities in Ningbo, Zhejiang, taking Changguo Wei as an example, this paper identifies the event characteristic space formed based on the coastal defense pattern and the local base space formed based on the endogenous evolution mechanism, and puts forward the characteristic protection methods of coastal defense settlement heritage.