The　aim　of　the　study　is　to　explore　the　possibility　of　detecting　metastatic　lymph　nodes　by　FTIR　spectra　during　the　surgery　of　thyroid　cancer.　The　FTIR　spectra　of　20　metastatic　lymph　nodes　and　69　non-metastatic　ones　were　collected　via　an　ATR　(attenuated　total　reflectance)　probe.　For　each　spectrum,　28　variables　of　13　bands　including　peak　positions　and　relative　intensities　were　measured.　The　variables　of　metastatic　lymph　node　were　compared　to　those　of　non-metastatic　ones　using　standard　statistic　methods.　The　results　indicated　that　the　FTIR　spectra　of　metastatic　lymph　nodes　were　significantly　different　from　non-metastatic　ones　in　the　bands　related　to　protein,　lipid,　nucleic　acid　and　carbohydrate.　(　1)　Variations　of　bands　related　to　protein:　The　relative　intensity　ratios　Of　I-3　280/I-1　460,　I-1　640/I-1　460　and　I-1　546/I-1　460　increased　significantly　(P＜0.05);　(2)　Variations　of　bands　related　to　lipid:　The　relative　intensity　ratios　of　I-1　743/I-1　460　decreased　significantly　(P＜0.05).　On　the　contrary,　I-1　400/I-1　460　increased　significantly　(P＜0.05);　(3)　The　peak　positions　of　1　165　and　1　120　cm(-1)　which　were　all　assigned　to　carbohydrate　shifted　toward　higher　wave　number　(P＜0.05).　The　relative　intensity　ratio　of　I-1　165/I-1　460　decreased　significantly　(P＜0.05);　(4)　The　peak　positions　of　1　085　cm(-1)　related　to　nucleic　acid　shifted　to　the　lower　wave　number　(P＜0.05);　(5)　Other　undetermined　bands:　The　relative　intensity　ratios　of　I-1　303/I-1　460　and　I-1　303/I-1　240　increased　significantly　(P＜0.05).　FTIR　spectroscopy　could　be　a　reliable　and　practicable　method　for　metastatic　lymph　nodes　diagnosis　in　the　operation　of　thyroid　cancer.　It　could　be　applied　in　detecting　metastatic　lymph　nodes　which　can　not　be　determined　by　palpation　in　surgery.