Abstract: Automated depth contour simplification is one of the common studying content in chart generalization. There are some problems such as inaccurately recognized bends and incompletely simplified bends in existing simplification methods. To overcome the drawbacks, a simplification method based on constrained Delaunay triangulation (CDT) is proposed. Firstly, CDT is constructed to achieve the binary tree representation of depth contour. Secondly, detection of bends which needs to be simplified is improved based on CDT. Finally, variety of generalization tools are designed and a new simplification model is built to realize the complete simplification of bends on depth contour. Tests illustrate that the proposed method meets navigation safety requirements, and the main bend characters are retained and represented clearly. The position accuracy meet the request of chart production. Besides, self-intersect can be avoided validly.