Sweet potato flour is a semi-finished product that can be used as raw material in the production of cookies, cakes, breads, and other bakery products. However, the resulted flour of purple sweet potato will undergo a color changing, becoming pale purple and non-uniform as a result of the degradation of anthocyanin pigments occurring in the processing process, a condition that consumers do not like. This study was to determine the standardized size of sweet potatoes cuttings and duration of steaming to produce purple sweet potato flour with a deep purple color, uniform and high anthocyanin content, so that the physical appearance of purple sweet potato will be preferably by consumers. Research method used was experimental method of Randomized Block Design, consisting of 6 treatments and 3 times repetitions. The results show that sweet potato with chips form of 3 cm and the duration of steaming of 35 minutes gave sweet potato with the best characteristics, e.i 6.61 pH, color intensities of L, a* and b* were 22.46, 9.05 and -5.43 respectively, 4464.62 ppm (mg/kg) anthocyanin, 11.5% total starch and 13,04% degree of gelatinisation.