Abstract: Purple starch was a kind of food with high nutritional value. It would play an important and extensive role in food industry. Starch was the main component of purple potato, of which physicochemical properties would affect final properties of purple potato products. In this study, physicochemical properties of starch from two kinds of purple potatoes, named ‘Ziyun one’ and ‘Black beauty’ were studied and compared with that of normal potato starch. Through image particle analysis, polarization cross analysis and X-ray diffraction pattern analysis, the results showed particle size, morphology as well as crystal type of purple potato starch was similar to normal potato. Further studies showed that the total starch content between purple potato starch and the normal potato starch have no significant difference (p>0. 05) , but the amylose content of purple potato was much higher. The transmittance, freeze-thaw stability and anti-aging effect of purple potato starch was lower than that of normal potato starch, and the sedimentation volume, peak viscosity was higher. In addition, purple potato starch needed much less energy in the gelatinization process.