Human language capabilities are acquired during infancy. We hypothesized that language brain circuit emergence is supported by rapidly increasing regional cerebral blood flow (rCBF) to meet the metabolic demands. However, the spatiotemporal distribution of rCBF in language network during infancy is unknown. In this study, we acquired resting-state fMRI and pCASL perfusion MRI from 48 infants aged 0-24months for identifying language network and quantifying rCBF, respectively. Heterogeneous and significant age-dependent rCBF increases were found at specific functional regions of language network during this critical period.