A method for product disassembly sequence planning is proposed under a par tial destruction mode based on partial destruction. Directed graph of assembly is used to show the relationships among the parts and the connecting pieces of products. Based on the directed graph of assembly, the relationship matrix, connecting matrix and reach ability matrix are defined. By iterating and calculating on these matrixes, the assembly structure and the assembly depth are obtained, which are used to determine the destructed objects, thus completing the disassembly sequence planning in partial destruction mode. Finally, the proposed method is verified by an example of the friction driven device. The result of sequence planning illustrates that the method is feasible and effective.