Abstract: The tender shoots and fruits of peach, pear and apple in April to August were used as materials, the ultrasonic-assisted extraction and high performance liquid chromatography were used to study change of the content of amygdalin in shoots and fruits, in order to provide reference for the distribution characteristics of amygdalin and its dynamic changes of content with time in the host plants of G.molesta.The results showed that the content of amygdalin in peach tender shoots(3.14 mg·g^-1) was much higher than that in apple tender shoots(0.28 mg·g^-1),but amygdalin was not detected in pear tender shoots.The contents of amygdalin in fruits of different host plants increased at first and then decreased, and reached the maximum in June, which in fruits of peach, pear and apple were 0.86 mg·g^-1,0.51 mg·g^-1and 0.43 mg·g^-1,respectively.In May and June, amygdalin was not detected in pears and apples, or significantly lower than in peaches.In July and August, only a small amount of amygdalin was found in pears and apples, while amygdalin was not detected in peaches.The content of amygdalin in peach tender shoots was significantly higher than that in peach fruits, and the content of amygdalin in apple tender shoots was significantly higher than that in apple fruits of May, July and August.Host plants were divided into three groups by cluster analysis, the first group only included peach tender shoots in April, the second group only included peach fruits in June, and the third group included the rest of host plants.Therefore, the content of amygdalin measured in different host plants had obvious seasonal difference.In early season, larval edible parts of peach trees contained more amygdalin than pear and apple trees.In late season, larval edible parts of pear and apple trees contained more amygdalin than peach trees, but lower than peach trees of early season.