Abstract: During Tween-assisted aqueous extraction of peanut oil,the simultaneously obtained aqueous phase was rich with peanut protein.With protein purity,residual oil content,protein recovery and Tween 20 content as evaluation indexes,recovery process of peanut protein powder was optimized in this study,intending to receive high-quality peanut protein powder.Alkali salt saponification,hexanes extraction and high speed centrifugation pretreatment were compared.Acid precipitation and ultrafiltration recovery of peanut protein were both investigated.Protein recovery rate was increased significantly at pH 4.5 by optimizing the pH acid precipitation phase.Protein recovery rate decreased and protein purity rose with the increase of washing times.Protein recovery rate decreased significantly,and protein purity leveled off after washing twice.The acid precipitation pH 4.5 and wash times were decided.By combining of alkali salt saponification method with acid precipitation process,the purity of obtained peanut protein powder was 81.28%,residual oil content was 5.18%,and Tween 20 content was 11.11%,and protein recovery was 84.68%.By using 5 kDa ultrafiltration membrane,peanut protein powder purity was 77.35%,residual oil content was 6.14%,Tween 20 content was 6.36%,and protein recovery was 97.45%.Compared with ultrafiltration,peanut protein powder of acid precipitation had high purity and low residual oil content,ultrafiltration had low Tween 20 content but the purity was not high.