Polysaccharide　from　Grifola　frondosa　is　one　of　the　best　metal-ion　chelating　agents　because　of　its　structural　characteristics　and　excellent　functional　activities.　In　this　study,　we　synthesized　and　characterized　a　novel　Grifola　frondosa　polysaccharide-chromium　(III)　[GFP-Cr(III)]　complex.　Response　surface　methodology　(RSM)　was　used　to　optimize　the　reaction　conditions　for　the　maximum　chelation　rate　of　GFP-Cr(III)　complex.　The　optimal　reaction　conditions　obtained　from　RSM　were　as　follows:　concentration　of　CrCl　3　6.97　mg/mL,　pH　7.75　and　temperature　71.73　°C,　respectively.　The　pH　was　the　most　significant　factor,　followed　by　reaction　temperature　and　concentration　of　CrCl　3　.　Under　the　deduced　optimal　conditions　(CrCl　3　7.0　mg/mL,　pH　7.7　and　temperature　70.0　°C),　the　experimental　chelation　rate　was　28.01%　±　0.18%　for　GFP-Cr(III)　complex,　which　agreed　closely　with　the　predicted　value　(27.61%).　Fourier　transform　infrared　(FTIR)　spectroscopy　revealed　that　the　primary　sites　of　chromium　(III)-binding　in　polysaccharides　were　O–]H　and　C[dbnd]N　groups,　leading　to　the　structure　of　GFP-Cr(III)　complex　was　loose　than　the　original　polysaccharide.　Nevertheless,　Cr(III)　did　not　make　a　fundamental　change　in　the　structure　of　GFP　when　comparing　the　FTIR　spectra　of　GFP　and　GFP-Cr(III)　complex.　Additionally,　the　effects　of　GFP-Cr(III)　complex　on　hyperglycemia　and　hyperlipidemia　in　high-fat　diet　(HFD)　and　streptozotocin　(STZ)-induced　diabetic　mice　were　also　investigated.　Results　showed　that　the　serum　total　cholesterol　(TC),　total　triglyceride　(TG),　low　density　lipoprotein　cholesterol　(LDL-C),　fasting　blood　glucose　levels　and　glucose　tolerance　in　diabetic　mice　fed　a　high-fat　diet　(HFD)　supplemented　with　GFP-Cr(III)　complex　(900　mg/kg　day)　were　significantly　lower　than　the　diabetic　group　(P　<　0.01).　These　results　suggest　that　GFP-Cr(III)　complex　could　be　used　as　potential　functional　food　ingredients　for　the　prevention　or　treatment　of　hyperglycemia　and　hyperlipidemia.　©　2019