Abundant　damage　information　is　implicated　in　the　bilinear　time-frequency　distribution　of　structural　dynamic　signals,　which　could　provide　effective　support　for　structural　damage　identification.　Signal　time-frequency　analysis　methods　are　reviewed,　and　the　characteristics　of　linear　time-frequency　distribution　and　bilinear　time-frequency　distribution,　typically　represented　by　the　Wigner-Ville　distribution,　are　compared.　The　existence　of　the　cross-term　and　its　application　in　structural　damage　detection　are　demonstrated.　A　method　of　extracting　the　dominant　term　is　proposed　that　combines　the　short-time　flourier　spectrum　and　Wigner-Ville　distribution.　Then　a　two-dimensional　time-frequency　transformation　matrix　is　constructed,　and　the　complete　cross-term　is　extracted.　The　distribution　character　is　in　favor　of　the　structural　damage　identification.　Through　theoretical　analysis,　model　experiments　and　numerical　simulation　of　the　girder　structure,　the　change　rate　of　the　cross-term　amplitude　is　validated　to　identify　the　damage　location　and　degree.　The　effectiveness　of　the　cross-term　of　the　bilinear　time-frequency　distribution　for　damage　detection　is　confirmed,　and　the　analytical　method　of　damage　identification　used　in　structural　engineering　is　available.　©,　2014,　Nanjing　University　of　Aeronautics　an　Astronautics.　All　right　reserved.