Abstract: The Process Conditions for Essential oil from poon-kan seed by ultrasonic-assisted solvent were studied. The physicochemical properties and the fatty acid composition were analyzed. The results showed that the yield of essential oil was 40.49% at the conditions of 250W ultrasonic power, 1∶7 solid-liquid ratio and 120s for extraction, and the physicochemical indexes of essential oil meet the requirement. Analysis of gas chromatography-mass spectrometry (GC-MS) showed that essential oil from poon-kan seed including Linoleic Acid (36.0721%), oleic acid (28.1571%), palmitic acid (29.5704%), stearic acid (3.4877%), linolenic acid (2.71%), and unsaturated fat was 66.9418%.