Contrastive focus highlights the important information in discourse, acoustically manifested in fundamental frequency (F0) and duration. In tonal languages, F0 conveys both lexical (lexical tones) and discourse meanings (contrastive focus). Given the importance of tones in word recognition, children acquire tonal productions early before age 3, but it was unclear when and how children acquire contrastive focus. This study tested 190 7-13-year-olds and 20 adult controls. Their productions of noun phrases with and without contrastive focus were elicited and perceptually evaluated for the presence/absence of focus. The perceptual judgement revealed that the perceived accuracy improved from 76% at age 7 to 93% at age 13. The acoustic analysis on the “perceived focus” productions revealed that 7-year-olds were able to use both F0 and durational cues, although fine-tuning continues until 13 years. These findings revealed that focus acquisition in Mandarin might be a late and gradual process.