Abstract: With assembly model organized in hierarchical and relational mode, the problem of automatically generating assembly and disassembly sequence is explored using cut set theory. In order to avoid graph explosion and improve the cut set algorithm's efficiency to solve the sequences, two new rules for judging the feasibility of cut set are put forward, as well as a hierarchical stragegy is adopted. Finally, with evaluating all the feasible assembly and disassembly sequence the method of selecting the optimize sequence and generating feedback recommend for designer is developed.