Abstract: An extended-feature information model based on knowledge and an extended-feature CSG tree method for recording design history are proposed in the paper. The extended-feature information model is constructed on the encapsulation of design knowledge and the extended-feature. Based on this model, CSG tree method is used to describe the design process. The extended-feature information model and extended-feature CSG tree are stored in a XML formatted extended-feature table to save the design process. By importing and parsing the XML formatted extended-feature table, the design process is reconstructed and the design knowledge is reused. At last, an example of turbine blades design is given to show the design process saving and reconstruction.