As　one　of　the　highest　energy　consumption　and　pollution　industries,　the　iron　and　steel　industry　is　regarded　as　a　most　important　source　of　particulate　matter　emission.　In　this　study,　chemical　components　of　size-segregated　particulate　matters　(PM)　emitted　from　different　manufacturing　units　in　iron　and　steel　industry　were　sampled　by　a　comprehensive　sampling　system.　Results　showed　that　the　average　particle　mass　concentration　was　highest　in　sintering　process,　followed　by　puddling,　steelmaking　and　then　rolling　processes.　PM　samples　were　divided　into　eight　size　fractions　for　testing　the　chemical　components,　S(O4)(2-　)and　NH4+　distributed　more　into　fine　particles　while　most　of　the　Ca2+　was　concentrated　in　coarse　particles,　the　size　distribution　of　mineral　elements　depended　on　the　raw　materials　applied.　Moreover,　local　database　with　PM　chemical　source　profiles　of　iron　and　steel　industry　were　built　and　applied　in　CMAQ　modeling　for　simulating　SO42-　and　NO3-　concentration,　results　showed　that　the　accuracy　of　model　simulation　improved　with　local　chemical　source　profiles　compared　to　the　SPECIATE　database.　The　results　gained　from　this　study　are　expected　to　be　helpful　to　understand　the　components　of　PM　in　iron　and　steel　industry　and　contribute　to　the　source　apportionment　researches.