Abstract: In order to determine the best preparation conditions of granular cold-water soluble sweet potato starch, the alcohol alkali method was used to prepare the sweet potato starch. The effects of reaction temperature, reaction time, amount of sodium hydroxide solution, proportion of water to starch (dry basis)and proportion of anhydrous ethanol to starch (dry basis) on the solubility of cold water were analyzed. The best preparation conditions for granule cold-water soluble sweet potato starch were as follows: reaction temperature is 33.9℃, reaction time is 22 min, sodium hydroxide solution dosage is 18.1g, ratio of water to starch (dry basis) is 3.6∶1, ratio of anhydrous ethanol to starch (dry basis) is 3.8∶1. The cold water solubility of sweet potato starch prepared under this condition is 89.07%.