Disclosed is method for preparation of a starch phosphate using phytate. The method enables the preparation of a starch phosphate with improved physical properties such as high transparency, solubility, swelling power, and storage stability by the phosphorylation of a starch using naturally occurring phytate rather than using a synthetic chemical. Due to these advantages, the starch phosphate is expected to replace conventional chemically modified starches. In addition, the method enables the preparation of a starch phosphate based on a simple modification. The use of the starch phosphate greatly contributes to improvements in the quality and storage stability of various starchy foods. Therefore, the starch phosphate is expected to find application in the food industry, including starchy foods.