Abstract: The slowly digestible starch is a new-type functional starch and it has many kinds of physiological functions. Waxy maize starch was taken as raw materials. Enzyme modified technology and moist heat-cooling technology were used to make slowly digestible starch and determine its optimized technological conditions. The results showed that the pullulanase concentration was 9 U/g, the enzyme reaction time was seven hours, the concentration of starch was 12.5%, the heat treatment time was 50 minutes, heat treatment temperature was 110℃, storage temperature was 1℃, storage time was two days and drying temperature was 60℃. Three repeated experiments were carried out under those conditions and the yield of slowly digestible starch was 27.33%.