Abstract: In this research, we sprayed 0.3% calcium chloride, 5 mmol L^-1 EGTA, 4% sucrose solution on the surface of leaves to explore the interactions of the total soluble sugar, sucrose, and starch content as well as the relevant enzyme activity of Chinese chestnut "yan shan zao feng" in the fruit establishment stage. The results indicated that: the sprayed sucrose solution increased soluble sugar, sucrose, and starch content, extended the duration of starch accumulation, and promoted sucrose synthase (SS), sucrose phosphate synthase (SPS), ADPG Pyrophosphorylase (AGPPase), soluble starch synthase (SSS) and granule-bound starch synthase (GBSS) activities. Individual fruit weight increased by 5.15%. CaCl₂ showed no significant effect on growth and development indexes of Chinese chestnut, while EGTA treatment reduced the single fruit weight, disturbed the Chinese chestnut kernel development amd caused formation of Empty-shell, inhibited the activity of SS, SPS, AGPPase, SSS and GBSS, and reduced the soluble sugar, sucrose, starch content. Spraying sucrose solution during the Fruit Growth and Development of Chinese chestnut is one of operational measurements.

Key words: Chinese chestnut, sugar metabolism, starch accumulation, enzyme activities, regulation