For　a　smart　isolated　system　with　distributed　parameters,　a　bidirectional　piezoelectric　variable　friction　control　device　with　function　of　isolation　and　control　was　designed.　This　control　device　could　produce　control　force　in　two　orthogonal　directions.　The　relation　equation　of　control　force　with　input　voltage　for　this　control　device　was　presented.　According　to　the　conditions　of　this　control　device　producing　control　force,　the　semi-active　control　algorithm　applicable　to　the　vibration　control　of　the　system　with　this　control　device　was　deduced.　Finally,　one　bidirectional　piezoelectric　variable　friction　control　device　was　simulated　numerically　and　used　for　smart　isolation　of　a　system　with　distributed　parameters　with　the　semi-active　control　algorithm　and　the　sequential　optimal　modal　control　algorithm　based　on　full　state　observers.　Simulation　results　showed　that　the　control　system　has　the　excellent　control　effect.