This study investigates how children acquire prosodic focus-marking in Mandarin Chinese. Using a picture-matching game, we elicited spontaneous production of sentences in various focus conditions from children aged four to eleven. We found that Mandarin Chinese-speaking children use some pitch-related cues in some tones and duration in all tones in an adult-like way to distinguish focus from non-focus at the age of four to five. Their use of pitch-related cues is not yet fully adult-like in certain tones at the age of eleven. Further, they are adult-like in the use of duration in distinguishing narrow focus from broad focus at four or five but in not using pitch-related cues for this purpose at seven or eight. The later acquisition of pitch-related cues may be related to the use of pitch for lexical purposes, and the differences in the use of pitch in different tones can be explained by differences in how easy it is to vary pitch-related parameters without changing tonal identity.