To　examine　the　damping　ratio　and　its　influence　on　seismic　response　of　the　maintenance　hangar,　firstly,　the　equivalent　structures　concept,　which　is　through　potential　energy　and　damping　ratio　shared　by　structural　members　with　different　materials,　was　used　to　obtain　the　damping　ratio.　Additionally,　the　related　program　was　developed.　According　to　the　program,　the　damping　ratio　for　the　interest　structures　with　three　kinds　of　span　is　determined.　Meanwhile,　the　value　of　damping　ratio　which　varied　with　the　stiffness　change　by　the　RC　columns　was　discussed.　Finally,　based　on　two　kind　of　damping　ratio,　such　as　value　calculated　from　method　mentioned　in　the　paper　and　value　selected　in　practical　design,　the　difference　of　the　seismic　response　from　two　types　damping　ratio　are　compared.　It　is　shown　that　the　damping　ratio　of　double-layer　diagonal　on　diagonal　space　frame　supported　by　the　RC　columns　is　below　0.0235,　which　is　smaller　than　the　0.03　damping　ratio　for　the　current　practical　design.　Therefore,　the　damping　ratio　should　be　analyzed　specifically　for　evaluating　the　dynamic　behavior　of　hangars.　The　stiffness　of　the　RC　columns　has　minor　impacting　on　the　damping　ratio.　For　practical　design,　if　the　span　of　hangar　is　larger　than　100　m,　0.023　would　be　reasonable　damping　ratio.　The　seismic　responses　calculated　with　calculating　damping　ratio　are　10%-20%　larger　than　the　result　from　damping　ratio　for　practical　design.