A　combined　method　based　on　variational　mode　decomposition　(VMD)　and　synchrosqueezing　wavelet　transform　(SWT)　was　proposed　to　identify　instantaneous　frequencies　from　multi-component　response　signals　of　civil　engineering　structures.　The　wavelet　scalogram　was　first　introduced　to　estimate　the　number　of　the　components　contained　in　a　response　signal.　Then,　the　VMD　was　used　to　decompose　the　response　signal　into　several　mono-components　self-adaptively　and　the　SWT　was　performed　on　the　decomposed　component　signals　to　extract　their　instantaneous　frequencies.　A　multi-component　simulation,　an　aluminum　cantilever　beam　test　with　abrupt　mass　reduction　and　a　steel　cable　test　with　time-varying　tension　forces　were　used　to　verify　the　effectiveness　and　accuracy　of　the　proposed　method.　The　results　demonstrated　that　the　proposed　method　performs　better　than　the　traditional　Hilbert-Huang　transform　and　the　continuous　wavelet　transform.　©　2018,　Editorial　Office　of　Journal　of　Vibration　and　Shock.　All　right　reserved.