Abstract: The fruit of pineapple cultivar‘Smooth Cayenne’（Ananas comosus） cultured under similar management conditions were harvested in winter（February）and summer（July）to determine their sugar content and their metabolism-based enzyme activities in relation to their growth and development. The pineapple fruit harvested in February showed a non-typical single‘S’pattern（fast-slow model）in their growth and development，while those harvested in July displayed a typical single‘S’pattern （slow-fast-slow model），and the fruit harvested in July matured 40 days earlier than those harvested in February. The fruit growth period had an effect on the sugar accumulation of the pineapple fruit. The ratio of hexose to sucrose was 0.37 in the fruit harvested in February with more sucrose accumulated，and 5.92 in the fruit harvested in July with more hexose. Significant difference in sugar accumulation and sucrose metabolism enzymes was observed between the fruit harvested in February and July. The higher sucrose content in the fruit harvested in February was mainly related with the higher activities of SPS and SS synthesis and the lower invertase activity in the fruit，whereas the lower sucrose content in the fruit harvested in July was mainly related with the higher invertase activity in the fruit. This revealed that different fruit growth periods had some impact on the growth and development and sugar metabolism of the pineapple fruit.

Key words: pineapple, Ananas comosus（L.）Merr., different growth period, sugar accumulation, enzyme related to sugar metabolism