A　horizontally　symmetric　all-metallic　vibration　isolator　(AM-VI)　is　proposed　to　further　investigate　the　dynamic　mechanical　performance.　The　novel　AM-VI　was　constructed　by　combining　hat-shaped　metal　rubber　and　oblique　springs,　which　were　connected　in　parallel.　The　springs　were　arranged　symmetrically　relative　to　the　support.　The　elliptic　method　and　the　frequency　sweeping　method　were　used　to　compare　the　dynamic　stiffness　and　the　loss　factor　of　the　AM-VI.　The　results　demonstrated　that　the　dynamic　stiffness　and　the　loss　factor　calculated　by　two　distinct　test　methodologies　were　considerably　different,　indicating　that　the　inertial　force　effect　of　the　dynamic　testing　equipment　should　be　taken　into　count　when　adopting　the　elliptic　method.　Furthermore,　when　the　vibration　isolation　performance　was　evaluated　by　utilizing　mechanical　impedance　and　force　transmissibility,　the　AM-VI　achieved　excellent　vibration　isolation　performance　within　a　broad　frequency　range.