Abstract: In order to more effectively plan applicable assembly sequence and detect interference occurred during assembly, a hybrid method is presented for assembly sequence modeling that introduces interactive guidance to build the main assembly sequence, and applies hybrid graph to automatically generate the sub-assembly sequences. In such a way, the processes of assembly sequence planning and evaluation are merged together under the same 3D geometric model. A system, namely KMCAAPP, is implemented on the platform of our earlier product KMCAD3D. Case study shows that it is capable of handling complicated CAD assembly models and timely identifying design errors.