In order to improve the quality of flax oil, the conventional hydration method was used to optimize the degumming process conditions and analyze the main physicochemical indexes. Taking the degumming rate as an indicator, the effects of temperature, time, water addition and phosphoric acid addition on the degumming effect of flax seed oil were studied respectively. Optimizing the degumming conditions of flax seed oil based on single factor and Box-Behnken center combination experimental design principle. The results showed that the best process conditions for degumming by conventional hydration method of flax seed oil: the temperature of 63.7 ℃, the time of 33.8 min, the amount of water added of 3.30%, and the amount of phosphoric acid added of 0.45%. The model predicts the degumming rate of flax seed oil is 79.65%, and the measured value is 79.10%. After degumming, the color, moisture, volatile matter, peroxide value, and acid value of flax seed oil meet the crude oil standard of flax seed oil.