Diclinism is not only an interesting natural phenomenon in plant kingdom, but also of significance in the yield of crops, e.g. cucumber and watermelon. Cucumber has been a model plant for studying the diclinism for decades. However, it is still obscure how the carpel primordia of cucumber male flower undergo the developmental processes after the initiation of their development. By showing morphological alternation, metabolic activity, as well asCFL gene expression, the present study demonstrated that the carpel primordia of cucumber male flowers maintained the characteristics of primordium until anthesis, although it developed significantly slower than that of the female flowers.