Abstract: The effects of concentration and treatment time of sodium sulfite on functional properties ( solubility, emulsifying activity and emulsion stability, foaming capacity and foam stability, water absorption, oil holding capacity and gel properties) of peanut protein concentrate were investigated.The results showed that the functional properties of peanut protein concentrate were significantly improved after the treatment of sodium sulfite, and the optimal condition of sodium sulfite treatment was: the concentration of sodium sulfite 0.75 mmol /L, treatment time120 min. The treatment of sodium sulfite for peanut protein concentrate efficaciously improved its functional properties, and was an available way of modification of peanut protein concentrate.