Though there are already a varlety of models for comples, they are not so convenientneeded in practice. A hlerchical model and the principle of decomposition and reconstitution for complex surfaceshave beem proposed, which have the potential to enhance the support of automated design systems on creative work intelligently. Then the progress made is discused involving the application of the new principle in the following threeareas; conugation sudace calculation, tool path generation in numercally controlled machining, and maching proccessinnovation By re-recognition.