To　meet　the　needs　of　safety　assessment　of　large　and　complex　plate　structures,　a　Lamb　wave　health　monitoring　technique　for　stiffened　metal　plate　structures　based　on　compressed　sensing　is　developed.　The　dispersion　characteristics　of　Lamb　waves　in　stiffened　panel　structures　are　recovered　from　a　small　amount　of　testing　data　obtained　from　sparse　array　using　compressed　sensing　technology.　To　realize　large-scale　defect　detection　imaging　in　stiffened　panel　structures,　a　new　method　of　sparse　array　Lamb　wave　composite　imaging　combining　cosine　similarity　with　Pearson　similarity　is　proposed.　The　experimental　results　show　compressed　sensing　technology　can　recover　the　frequency-wavenumber　relation　of　Lamb　waves　in　stiffened　plates.　And　the　Lamb　wave　composite　imaging　method　can　detect　and　locate　single　and　multiple　defects　in　stiffened　panels.　Research　work　provides　a　feasible　technical　solution　for　detecting　damage　of　complex　plate　structure.　©　2019,　Press　of　Chinese　Journal　of　Aeronautics.　All　right　reserved.