A novel technology of foam separation to purify acidic fraction gum (AFG) has been established in this research. The effects of the operational factors, that is, initial feed concentration, pH of raw solution and the volume of liquid and the temperature of foam separation have been investigated. Response surface methodology (RSM) was used to optimize conditions of foam separation for AFG, the optimum conditions were as follows, initial feed concentration 112.86 mu g/mL, the pH 3, volume of liquid 202.37 mL, and temperature 20.77 degrees C. Under this condition, enrichment ratio and recovery reached the highest of 14.8 and 79.1%, respectively. It has been found that purification of AFG by foam separation is an effective, simple equipped, low energy consuming, and potential industrial technology.