Abstract: Linear features take an important part of features on map. Generalization of linear features not only is data compress of geometric characteristics, but also needs researching spatial structure relationship of geographical characteristics, which is connotative among linear features. Spatial structural characteristic of curve is analyzed based on bends as a basic structure unit of curve. A structural method of curve shape is proposed, that is using constraint Delaunay triangulation network model, considering Gestalt principle, partitioning the structure of curve shape, dividing curve bends into basic bends and complex bends, and identifying the bend characteristics, method of detecting and expressing spatial structural relationship among bends is given, finally, bend and its structural relationship are class encapsulated by object oriented method. According to experiments’ results，compared with the model of binary tree representation of curve hierarchical structure in depth, the method is more better in curve bend definition, maturity of spatial structural characteristics representation of curve, and line simplification results using the method.