Abstract: Pumpkin polysaccharide,which have health effects and disease treating functions,is the main active ingredients of a study of extracting pumpkin.In this paper,a study of extracting pumpkin polysa-ccharide from pumpkin under ultrasound irradiation with water as solvent is made.Effects of premarinating time,ultrasound power,time and on/off ratio of ultrasonic irradiation on pumpkin polysaccharide extraction are investigated.Experiments show that taking 10 min premarinating time at 60℃,80W ultrasound power and 20 minutss of ultrasound processing time with on/off ratio being 1,the maximum extraction yield(42.6 mg/g) can be obtained.