Background: Rapid automatised naming (RAN) has been found to predict children's reading and arithmetic abilities. However, the underlying mechanisms for its involvement in the two abilities are not clear. This study examines how RAN shared variances with domain-general and domain-specific abilities in predicting reading and arithmetic in Chinese children. Methods: One hundred and sixty-four children (mean age = 8 years 0 months, SD = 4 months) were administered with RAN tasks, word reading and arithmetic tasks and measures of working memory, processing speed, morphological awareness, phonological awareness and number line estimation. Results: RAN mainly shared variance with morphological awareness in predicting word reading, while it shared variance with processing speed and number line estimation in predicting arithmetic calculation. Conclusions: The findings indicated that RAN was related to reading and arithmetic for different reasons. The RAN-reading relationship partly reflected the semantic facilitation of the orthography-phonology links for both RAN stimuli and Chinese characters, while the RAN-arithmetic relationship partly reflected the shared process of retrieving semantic information from long-term memory embedded in the two tasks.