Abstract: The forward extraction of red kidney bean protein (RKBP) by reverse micelles was studied. The reverse micelles system was formed by di-2-ethylhexyl sodium sulfosuccinate (AOT) , isooctane and KCl buffer solution. The effect of AOT concentration on water content and the critical volume of water in reverse micelles formed by AOT, isooctane and water were investigated by measuring electrical conductivity. The effects of AOT concentration, pH value of buffer solution, KCl concentration and extraction time on the forward extraction yield were investigated. On the basis of single-factor experiments, the technical condition was optimized by orthogonal tests. The results indicated that the volume of water which could be solubilized in the system increases with the increase of AOT concentration, while the critical water contents of the reverse micelles remained almost the same value. The results of orthogonal tests showed that the top forward extraction yield of RKBP was reached at the condition of AOT concentration 1. 25mol/L, pH7. 5, KCl concentration of 0. 05mol/L, extraction time 90min. Under the optimum technical condition, the forward extraction yield of RKBP achieves 43. 57%.