In　many　applications,　the　structural　operating　conditions　may　significantly　differ　from　those　applied　during　laboratory　tests　where　the　structure　is　well　known,　well　installed　and　properly　excited.　For　structures　under　their　natural　loading　conditions,　or　excited　by　random　forces,　excitations　cannot　be　measured　and　are　usually　non　stationary.　Hence,　an　improvement　operational　modal　analysis　is　a　useful　complement　to　the　traditional　modal　analysis　approach.　The　aim　of　this　paper　is　to　present　the　application　of　a　new　identification　procedure,　named　wavelet　identification　technique,　for　structural　characterization.　The　wavelet　identification　technique　works　in　the　time-frequency　domain　and　is　used　to　identify　the　dynamic　characteristics　of　the　structural　system　in　terms　of　natural　frequencies,　damping　coefficients　and　modal　shape,　especially　how　to　identification　the　modal　shape　through　operational　measurements　dynamics.　An　experimental　example　is　treated.　The　experimental　example　is　the　arch　bridge　in　Xining,　China　with　span　of　90m,　which　is　a　concrete　filled　steel　tubular　half-through　tied　arch　bridge.　The　eigenfrequencies,　damping　coefficients　and　modal　shape　of　this　bridge　excited　by　operational　measurement　are　obtained　using　the　wavelet　analysis　technology.　The　results　obtained　agree　with　those　previously　obtained　on　the　dynamic　behaviors　of　the　Beichuan　arch　bridge.