This study investigates Putonghua rhythm development among Uyghur preschoolers in South Xinjiang, China. We examined 40 children (ages 5-7) grouped by Putonghua learning time: mid-class (12 months, mean age 6;1) and senior-class (24 months, mean age 7;1). Speech samples were elicited through picture-guessing tasks and analyzed using rhythmic metrics. Our analyses reveal distinct developmental patterns compared to Putonghua-speaking children, with neither group achieving metrics comparable to age-matched Putonghua-speaking 6-year-olds. Consonant-related metrics emerged as increasingly salient markers in later developmental stages. The findings demonstrate that rhythm acquisition in this bilingual context is modulated by cross-linguistic influence from Uyghur. These results advance our understanding of L2 rhythm acquisition in bilingual settings and have implications for developing automated speech assessment tools and optimizing speech recognition systems for multilingual contexts.