Polysaccharide　from　Ganoderma　lucidum　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　G.　lucidum　polysaccharide　chromium　(III)　[GLP-Cr(III)]　complex.　Response　surface　methodology　(RSM)　was　used　to　optimize　the　reaction　conditions　for　the　maximum　chelation　rate　of　GLP-Cr(III)　complex.　The　optimal　reaction　conditions　obtained　from　RSM　were　as　follows:　concentration　of　CrCl3　5.71　mg/mL,　pH　636,　temperature　66.4　degrees　C　and　time　2.0　h,　respectively.　The　pH　was　the　most　significant　factor,　followed　by　reaction　temperature　and　CrCl3　concentration.　Under　the　optimal　conditions,　the　experimental　chelation　rate　was　94.17　+/-　1.0%　for　GLP-Cr　(III)　complex,　which　agreed　closely　with　the　predicted　value　(94.60%).　Fourier　transform　infrared　(Fr-IR)　spectroscopy　revealed　that　the　primary　sites　of　chromium　(III)-binding　in　G.　lucidum　polysaccharide　were　O-H　and　C-O　groups,　which　induce　the　morphology　change　from　flat　sheet　to　rough　surface.　Meanwhile,　according　to　the　result　of　X-ray　diffraction　(XRD),　the　crystal　degree　of　GLP　was　disappeared　after　chelation　with　Cr(III).　The　presence　of　a　＂blind　zone＂　in　the　H-1　NMR　spectrum　obviously　indicated　the　binding　of　Cr(III)　to　GLP.　Additionally,　the　effects　of　GLP-Cr(III)　complex　on　hyperglycemia　and　hyperlipidemia　in　high　fructose　and　fat　diet-induced　pre-diabetic　mice　were　also　investigated.　Results　showed　that　the　serum　total　cholesterol　(TC),　triglyceride　(TG),　low　density　lipoprotein　cholesterol　(LDL-C),　fasting　blood　glucose　levels　and　glucose　tolerance　in　mice　supplemented　with　GLP-Cr(III)　complex　(50　mg/kg　day)　were　significantly　lower　than　the　model　group　(P　＜　0.01).　More　importantly,　the　GLP-Cr(III)　complex　had　no　significant　adverse　effects　on　the　physiological　metabolism,　organ　index,　and　liver　tissue　morphology　of　mice　fed　a　normal　diet.　These　results　suggest　that　GLP-Cr(III)　complex　could　be　used　as　potential　functional　food　ingredients　for　the　prevention　or　treatment　of　hyperglycemia　and　hyperlipidemia.　(C)　2019　Elsevier　B.V.　All　rights　reserved.