A　wavelength　dispersive　X-ray　fluorescence　(WD-XRF)　spectrometry　combined　with　calibration　curve　method　was　established　for　simultaneously　analyzing　low-Z　elements　(C,　N,　O)　and　Al,　Si,　Fe　in　polyamide.　To　investigate　the　origin　of　plastic　material　causing　deposition　and　blocking　in　instrument　engines　and　pipelines,　polyamide　6　(PA　6,　an　engineering　plastic)　was　chosen　as　the　study　object　on　account　of　its　common　use　in　industry.　The　sample　preparation　with　pressed　powder　disk　has　been　developed　for　determination　of　six　elements　in　PA　6.　Pure　Cu　metal　was　used　as　the　matrix　and　PA　6　was　regarded　as　standard　sample　for　C,　N,　O　elements.　PA　6　particles　were　firstly　smashed　to　uniform　powder　in　liquid　nitrogen,　and　then　mixed　with　inorganic　standard　powders　(Fe　2O3,　Al2O3,　SiO2,　and　Na2SiO3).　The　mixture　was　ground　to　obtain　homogeneous　calibration　materials　for　WD-XRF　analysis.　The　quantitative　property　of　the　calibration　curve　method　for　each　element　was　reliable.　The　limits　of　detection　(S/N≤3)　of　C,　N,　O,　Al,　Si　and　Fe　using　WD-XRF　were　249,　120,　101,　6.2,　3.3,　and　1.8　μg/g,　respectively.　To　confirm　the　accuracy　of　the　proposed　WD-XRF　calibration　curve　method,　inductively　coupled　plasma　optical　emission　spectroscopy　(ICP-OES)　detection　for　Al,　Si,　Fe　and　elemental　analyzer　(EA)　analysis　for　C,　N,　O　were　utilized.　A　good　correlation　of　the　WD-XRF　results　with　the　measurements　of　ICP-OES　and　EA　was　observed.　©　2013　Science　China　Press　and　Springer-Verlag　Berlin　Heidelberg.