Abstract:Carboxymethyl pachymaran-Iron(Ⅲ)complex was synthesized by the reaction of carboxymethyl Poria cocos polysaccharide with FeCl3 under alkaline condition with sodium citrate as catalyst. pH， reaction temperature and the mass ratio of trisodium citrate to carboxymethyl pachyman were taken as factors and the preparation of carboxymethyl pachyman-Iron (Ⅲ)complex was optimized by response surface methodology on the basis of single factor experiment.The optimum conditions were as follows：pH was 8.3，reaction temperature was 72.9 ℃，the mass ratio of trisodium citrate to polysaccharide was 0.69，the model was well fitted and the iron content of CMPIC was 27.55%.Ultraviolet and infrared spectroscopy showed that the hydroxyl group of CMPIC had a stable complex with Fe3+and further antioxidant studies showed CMPIC had certain clearance ability to metal ions and ABTS +·. Therefore， CMPIC is expected to be further studied as a new iron-supplementing antioxidant.