Abstract:To analyze the changes of carbohydrate content and the activities of related enzymes in bearing branches and their effects on fruit setting before and after period of dormancy, and to provide theoretical basis for the transformation of almond low yield garden, we selected the same age and the same species in 2012-2014 under three consecutive years of sustained low yield and sustained high yield orchards as the research object, taking the main cultivated varieties ‘Zhipi’ as test material, analyze the contents of carbohydrate components and activities of related enzymes in the phloem and flower bud of bearing branches before and after the period of dormancy. Meanwhile, we also carried on the statistical analysis to the percentage of fruit set and the yield per tree, the results show that: (1) soluble sugar accumulation of bearing branches is basically about sucrose and sorbitol during dormancy. (2) The trend of carbohydrate content changes in the phloem and flower bud of bearing branches before and after period of dormancy is identical to the changes of activities of related enzymes(acid invertase, neutral invertase, sucrose synthase, sucrose phosphate synthase, ect.) in the highyield orchard and lowyield orchard. (3) The carbohydrate contents and related enzyme activities of bearing branches in highyield orchard are higher than those in lowyield orchard. It is thus clear that the level of carbohydrate accumulation of bearing branches during dormant period is one of the key factors that can influence the percentage of fruit set and the yield in the following year.