We　present　and　analyze　a　hybrid　quantum　system　that　interfaces　a　Majorana-hosted　semiconductor　nanowire　with　a　single　nitrogen-vacancy　(N-　V)　center　via　a　magnetized　torsional　cantilever.　We　show　that　the　torsional　mode　of　the　mechanical　resonator　can　strongly　couple　to　the　Majorana　qubit　and　the　spin　qubit　simultaneously,　which　allows　us　to　interface　them　for　quantum-state　conversion　through　a　dark-state　protocol.　This　work　provides　a　promising　interface　between　the　topological　qubit　and　the　conventional　spin　qubit.　This　interface　may　have　interesting　applications　in　quantum　information　and　computation.