A　dynamic　vibration　absorber　(DVA)　using　magnetorheological　(MR)　for　synchronous　stiffness　and　damping　control　is　detailed　in　this　study.　The　variable　longitudinal　vibration　frequency　of　propulsion　shafting,　which　is　attributed　to　a　broad　spectrum　of　propeller　speed　fluctuations,　necessitates　effective　vibration　mitigation.　Conventional　DVAs　suffer　from　limited　tunability,　which　can　lead　to　the　failure　of　optimal　resonance,　narrowed　vibration　suppression　bandwidth,　and　potential　vibration　exacerbation.　Thus,　a　control　criterion　for　optimizing　the　stiffness　and　damping　parameters　is　proposed　in　this　study.　Firstly,　a　longitudinal　vibration　dynamic　model　for　the　propulsion　shafting　system　is　developed,　to　determine　the　acceleration　transmissibility　and　resonance　frequency　points.　Next,　a　magnetorheological　vibration　absorber　(MRVA)　is　designed　to　encompass　synchronous　controlled　stiffness　and　damping.　The　mechanical　property　evaluations　and　frequency　shift　tests　confirm　the　absorber＇s　capacity　for　variable　stiffness　and　damping.　A　coupled　dynamic　model　that　integrates　the　propulsion　shafting　system　and　MRVA　is　established.　A　control　criterion　for　the　stiffness　and　damping　has　been　formulated　to　accommodate　the　diverse　working　conditions.　The　results　of　the　vibration　reduction　experiments　substantiate　the　efficacy　of　the　proposed　control　criterion,　thus　demonstrating　the　attenuation　of　acceleration　amplitude　above　37%,　besides,　up　to　90%　has　been　achieved　at　specific　frequencies.