Abstract: In order to research the contents and functions of sucrose in the course of mango differentiation, it was observed that after cutting back flowering branch of mango, the flower bud on the cutting place could still in differentiation, the author measured the sucrose content of leaves, phloem and buds on the cutting section. The results showed that: the cutting leaves and nearby phloem’s highest content appeared on the same day of cutting back, separately were 43.16 and 45.89μg/g, the buds’highest appeared on March 2nd (47.92μg/g); leaves, phloem and buds’lowest content separately appeared on March 12th, 7th and February 25th, were 38.47, 38.27 and 38.94μg/g; the average content of leaves, phloem and buds were 40.72, 41.34 and 42.93μg/g. It didn’t have a transport phenomenon that the sucrose flowed from the cutting parts to the organic centre (the buds at the differentiation), there was no clearly library-source relationship, and this indicated that sucrose didn’t have strongly correlation with flower bud differentiation, or the carbohydrate mainly not transported as the form of sucrose. After cutting back, the center color of bud eye gradually presented wax yellow on Feb 20th, and spread around on the 25th; during March 2nd to 7th, the buds gradually expanded, the color deepen, the buds eye presented translucent; after March 7th it was gradually increased green, and the translucent disappeared.