This　paper　presents　a　practical　and　user-friendly　finite　element　(FE)　model　updating　technique　for　real　structures　using　ambient　vibration　test　results.　The　first　case　study　of　a　simulated　simply　supported　beam　demonstrates　a　comparative　Study　of　the　influence　of　different　possible　residuals　in　objective　function.　Frequency　residual　only,　mode　shape　related　function　only,　modal　flexibility　residual　only,　and　their　combinations　are　studied　independently.　In　view　Of　timing　as　well　as　damage　localization,　full　objective　function　that　considers　all　three　residuals　is　the　best　for　FE　updating.　This　objective　function　is　implemented　in　a　second　case　study　of　a　real　concrete-filled　steel　tubular　arch　bridge.　The　bridge　was　tested　by　ambient　vibration　measurements.　Followed　by　the　three-dimensional　FE　modeling　of　the　bridge,　an　eigenvalue　sensitivity　study　is　carried　out　to　see　the　most　sensitive　parameters　to　the　concerned　modes.　FE　model　mass　matrix　obtained　from　Guyan　reduction　technique　is　used　to　the　mass　normalization　of　the　mode　shapes　extracted　from　ambient　modal　test　to　calculate　the　modal　flexibility.　The　updated　FE　model　of　the　bridge　is　able　to　produce　a　sufficient　improvement　on　modal　parameters　of　the　concerned　modes　which　is　in　close　agreement　with　the　experimental　results　still　preserving　the　physical　meaning　of　updated　parameters.