Abstract: To develop high-quality pectin resources,high methoxyl pectin from passion fruit peel was extracted by ultrasonic assisted citric acid method. The effects of the single factors(solid-liquid ration,pH value,extraction time,and ultrasonic power)on the yield of pectin were studied. Orthogonal test was designed to identity the optimal extraction process of pectin. The physicochemical properties of extracted pectin were compared and analyzed. The result of the process optimization experiments showed that extraction time had the most significant influence on extraction rate,followed by solid-liquid ration,pH value,and ultrasonic power. The optimum extraction conditions of pectin from passion fruit peel were shown as:Solid-liquid ration 1:40 (g/mL),pH value 2.00,extraction time 60 min,and ultrasonic power 180 W. Under these conditions,the extraction of pectin was 13.07%. The results from physicochemical analyses showed the weight loss was 5.92%,the ash contents was 4.18%,the acid insoluble matter contents was 0.27%,the pH value was 3.55,and the degree of esterification was 72.32%,which belongs to high esterification pectin. This conclusion would provide technical support for the industrial production of passion peel pectin.