Abstract:The protein was extracted from flaxseed flake using alkali soluble and acid sinking method.The effects of solid-liquid ratio，temperature and time of extraction and pH value on the extraction rate of flaxseed flake protein were studied by single factor experiment.The extracting conditions were optimized by response surface methodology.The results showed the optimum conditons were as follows：the solid-liquid ratio was 1∶36（g/mL），pH 10.9，time was 60 min，the extracting temperature was 39.7 ℃.Under these conditions，the yield of protein was 41.48 %.The main functional property of the protein extracting from flaxseed flake under the optimum conditions was studied.The functional property of protein includes solubility，water holding capacity，emulsion，foaming and foaming stability.The results showed that flaxseed flake protein had better solubility，water holding capacity and surface activity than soybean protein.