The effect of pH value, moisture content and temperature on modification of potato starch (PS) was studied. The result showed that after being treated by partial acid hydrolysis (AH) combined with heat moisture treatment (HMT), the amylose content in PS increased, while soluble amylose content decreased; Solubility and swelling power of most modified starches decreased; Peak viscosity (PKV), trough viscosity (TV), final viscosity (FNV), attenuation and setback decreased; But gel hardness of some modified starches was higher than native starch. The biggest hardness of starch gel was 143.42 g, which was about 4.2 times higher than native PS, while gel springiness and cohesiveness of all modified starches decreased. To, Tc, Tp and Tc-To of PS modified starches significantly increased, but ΔH decreased. Crystallized potato starch was B-type, the peak of modified PS at 5.9°(2θ) decreased, double peak at 22~25°(2θ) decreased too, and even became into a single wide peaks.