Memory binding is the ability to bind together multiple components in a memory trace. Previous studies have shown that one way to improve memory binding is to integrate multiple components into the same item in a meaningful way – a strategy known as unitization. To further investigate unitization as a source of development of memory binding, in terms of whether a unitization strategy has different effects on different memory structures and different age groups, the current study incorporated a semantic unitization strategy into a memory binding task and recruited multiple age groups for the experiment. Results showed that unitization led to a marked improvement in three-way binding for 7-year-olds and adults, but not for 5-year-olds, suggesting that semantic unitization could be a driving force for the development of complex memory binding in childhood and even beyond adulthood, but its effect in young children might still be limited due to their immaturity.