Optimum　installation　of　viscoelastic　dampers　in　space　frame　structures　is　investigated　in　this　paper.　The　principle　for　vibration　control　of　the　structure　is　introduced.　Control　objectives　are　determined　by　considering　nodal　displacement,　nodal　acceleration,　and　member　axial　forces,　separately.　A　computer　program　is　developed　for　optimum　analysis　of　control　performance.　The　effects　of　damper　arrangements,　positions,　numbers,　and　inclined　angle　of　damper　supporting,　and　so　forth,　are　analyzed　and　discussed.　A　comparison　is　made　between　vibration　reduction　efficiencies　under　different　cases　of　damper　installations.　It　is　indicated　that　optimum　installation　of　viscoelastic　damper　in　structures　will　significantly　improve　control　effectiveness　for　the　structure.　Finally,　fundamental　steps　for　optimization　of　viscoelastic　dampers　in　practical　structures　are　proposed.　Following　suggestions　are　provided　for　optimum　installation　of　dampers:　(1)　the　dampers　would　be　better　to　be　located　in　equally　divided　positions　along　the　span;　(2)　installing　dampers　along　longitudinal　side　is　better　than　along　transverse　side,　and　it　is　the　best　to　install　the　dampers　jointly　in　both　sides;　(3)　the　optimum　inclined　angle　of　damper　supporting　is　suggested　as　α=45°-60°;　(4)　connecting　dampers　to　the　lower　chord　of　the　structure　is　better　than　to　the　upper　chord;　(5)　the　number　of　dampers　should　be　properly　determined.　This　paper　provides　a　good　reference　for　practical　application　and　design　of　viscoelastic　dampers　in　space　frame　structures.