Numerous studies have evidenced the relationship between musical rhythm and language performances, derived from temporal acoustic signal processing. This relationship might be affected by different language experiences. Receptive and expressive vocabulary knowledge, phonological awareness, and musical rhythm perception and production were examined in Chinese-speaking (n = 112) and English-speaking preschoolers (n = 73), by using standardized or self-designed linguistic assessments, and musical rhythm discrimination and tapping tests. Generally, results evidenced a cross-language association between musical rhythm performance and vocabulary knowledge in preschoolers. Significant associations were found between receptive vocabulary knowledge and musical rhythm perception as well as production skills in Chinese-speaking pre-schoolers; while Chinese expressive vocabulary knowledge was only associated with musical rhythm production but not perception. As for the English-speaking fellows, both receptive and expressive vocabulary knowledge showed significant association with musical rhythm perception and production skills. Additionally, hierarchical regression analyses were implemented to explore the contribution of phonological awareness and musical rhythm performance towards vocabulary knowledge. Results exhibited that musical rhythm production skills effectively predicted the expressive vocabulary knowledge in Chinese-speaking preschoolers, whilst musical rhythm perception skills predicted the receptive vocabulary knowledge in English-speaking fellows. To note, none of any musical rhythm significantly predicted Chinese receptive vocabulary knowledge and English expressive vocabulary knowledge, suggesting a possible mediation role of phonological awareness to rhythm-vocabulary relationship. Our findings provide cross-language evidence for the robustness of the rhythm-language relationship and possible predictive effect between musical rhythm and specific vocabulary knowledge.