Particle　dampers　are　efficient　vibration　control　devices　and　are　widely　used　in　mechanical　engineering　and　aerospace　engineering;　however,　there　are　still　limited　applications　in　civil　engineering.　The　vibration　reduction　effects　of　particle　dampers　were　investigated　by　a　series　of　shaking　table　tests　of　a　three　storey　steel　frame　with　such　a　device.　It　is　shown　that　with　small　weight　penalty　(2.25%),　particle　damper　system　has　good　performance　in　reducing　the　seismic　response,　especially　the　r.　m.　s.　displacement　response.　However,　the　reduction　effects　are　influenced　by　the　excitation　characterization　and　the　vibration　amplitude　of　the　primary　structure.　Slug　flow　motions　lead　to　better　vibration　control　effects.