Abstract: The B-Rep-based feature model is not suitable for feature editing which leads to topological variations. The authors point out that using the geometric edge in the B-Rep as the location base of form feature is unsatisfied with topological variation after a case study. This paper presents the sketch-based designing procedure for parametric feature modeling and illustrates the importance for feature variational design. For the implementation, the authors present a new method which combines the B-Rep-based feature model and the sketch-based feature model together in the designing procedure. This method keeps the location base of form feature invariance during the feature modeling and editing, and it is suitable for feature parametric variational design and topological variation.