Abstract: Based on the single factor tests, the effects of mass ratio between lentinan and catalyst sodium citrate, pH reaction temperature on iron combination rate of lentinan- Fe ( Ⅲ) were designed using Box-Behnken to assess the combination rate of iron (Ⅲ) . A prediction model was established. The optimal synthesis conditions were mass ratio between lentinan and catalyst sodium citrate of 1.8, pH8.0, reaction temperature of 68.70℃, iron combination rate of lentinan-Fe (Ⅲ) was 11.69%. It was generally accepted that the response surface method was scientific and optimum for the synthesis of lentinan-Iron (Ⅲ) complex.