This study examined the longitudinal relation between early prosodic reading and later reading comprehension ability. Spectrographic analysis was conducted on six types of syntactic structures in Cantonese prosodic reading and English prosodic reading, with focus on pitch pattern and pause structure. Our results showed that longitudinal prediction of early prosodic reading to later reading comprehension ability occurred both within language and across languages. However, the prediction was limited to English prosodic reading. Moreover, only English pause structure but not pitch pattern was significant in predicting later English and Chinese reading comprehension. These findings shed light on the application of automaticity theory and lexical quality hypothesis in Cantonese-English bilingual context and demonstrate the importance of early prosodic reading in later reading comprehension ability.