Based　on　ICM　(Independent　Continuous　Mapping)　method　of　structural　topology　optimization,　a　model　with　weight　minimum　objective　and　displacement　amplitude　constraints　is　established　for　the　topology　optimization　problem　of　continuum　structure.　The　displacement　amplitude　is　close　expressed　by　the　first　order　Taylor　expression.　With　a　view　to　that　there　are　always　many　design　variables　in　the　topology　optimization,　and　the　partial　derivatives　with　respect　to　one　design　variable　can　be　obtained　from　a　sensitivity　analysis　in　the　direct　method,　an　adjoint　method　of　sensitivity　analysis　of　displacement　amplitude　with　frequency　response　is　developed　and　the　partial　derivatives　with　respect　to　all　design　variables　can　be　obtained　from　a　sensitivity　analysis.　Numeric　examples　reveal　that　the　computational　efficiency　can　be　improved　dramatically　if　sensitivities　are　analyzed　by　the　adjoint　method.　Adopting　the　topology　variables　which　independent　of　size　and　shape　parameters　of　structure　in　ICM　method　reflects　the　essence　of　topology　optimization　more　clearly.