Corn flour were mixed with defatted peanut flour at different ratio.After extruding,their functional characteristics and interrelation of each analyzed index were studied.The results indicated that,the radial expansion ratio and water injectivity index decreased with the increase of fraction of defatted peanut flour.Meanwhile the color was gradually darken.However,water soluble index was increased with the increase of defatted peanut flour.When defatted peanut flour reached to 25%,the gelatinisation degree of extrusion productions had the maximum value(98.92%),and better WAI and WSI.The mathematic models of each analyzed index were obtained.