Abstract: In order to solve the problem of high cost of commercial starch, fresh potatoes produced in Mianyang were as experimental materials and the optimized method for extraction of potato starch was determined by orthogonal design.Taking the yield of fresh potato starch as reference index, optimum process screened was obtained when smashing time was 2 minutes, along with 3 hours of rest time and 3 times of washing. The average yield of potato starch was 13.5% under the optimized condition.Then, based on the national standard method, the amylose of potato was extracted with the method of hot alkaline and purified through n-butanol and isoamyl alcohol recrystallization. Finally, its quality was evaluated. The result showed that the potato amylose preparating in laboratory could be used as a standard sample.