Abstract: In this study, high performance liquid chromatography (HPLC) was used to determine the contents of nobiletin, tangeretin, hesperidin, naringin, limonin and synephrine in the first physiological fruit drop of mandarin orange, orange and pomelo from the main Citrus producing areas in China, such as Yichang in Hubei, Huaihua in Hunan, Chaozhou in Guangdong, Nanning in Guangxi, Zhangzhou in Fujian and Quzhou in Zhejiang. The purpose of comparing the characteristics of the content of effective active components in young fruits of Citrus plants from different habitats was to select Citrus cultivars with high nutritional value and rich active components, so as to lay a foundation for further extracting effective components and applying them to all aspects in the future. The results showed that: The contents of nobiletin and hesperidin in tangerine young fruits in Zhejiang Province were the highest, which were 359.63 μg/g and 222.14 μg/g, respectively. The content of naringin in the young fruit of Hubei Changyang grapefruit was the highest, which was 20.97 mg/g. The content of hesperidin in young fruits of Hubei Newhall orange was the highest, which was 1485.73 μg/g. The content of limonin in the young fruit of Guanxi grapefruit in Fujian was the highest, which was 866.73 μg/g. The content of synephrine in the young fruit of fertile orange in Guangxi was the highest, which was 1004.14 μg/g.