Inspired　by　the　limb　structures　of　animals/insects　in　motion　vibration　control,　a　bio-inspired　limb-like　structure　(LLS)　is　systematically　studied　for　understanding　and　exploring　its　advantageous　nonlinear　function　in　passive　vibration　isolation.　The　bio-inspired　system　consists　of　asymmetric　articulations　(of　different　rod　lengths)　with　inside　vertical　and　horizontal　springs　(as　animal　muscle)　of　different　linear　stiffness.　Mathematical　modeling　and　analysis　of　the　proposed　LLS　reveal　that,　(a)　the　system　has　very　beneficial　nonlinear　stiffness　which　can　provide　flexible　quasi-zero,　zero　and/or　negative　stiffness,　and　these　nonlinear　stiffness　properties　are　adjustable　or　designable　with　structure　parameters;　(b)　the　asymmetric　rod-length　ratio　and　spring-stiffness　ratio　present　very　beneficial　factors　for　tuning　system　equivalent　stiffness;　(c)　the　system　loading　capacity　is　also　adjustable　with　the　structure　parameters　which　presents　another　flexible　benefit　in　application.　Experiments　and　comparisons　with　existing　quasi-zero-stiffness　isolators　validate　the　advantageous　features　above,　and　some　discussions　are　also　given　about　how　to　select　structural　parameters　for　practical　applications.　The　results　would　provide　an　innovative　bio-inspired　solution　to　passive　vibration　control　in　various　engineering　practice.