Abstract: The transition of South China Block from the Paleo-Tethyan to the Paleo-Pacific tectonic domain exerted a profound influence on regional tectonic evolution, sedimentary basin architecture, and magmatic activity. However, the timing of this critical tectonic regime transition remains contentious. This study focused on the Late Triassic-Middle Jurassic sedimentary rocks in Heyuan area of Eastern Guangdong Basin in South China, and conducted U-Pb chronology research on detrital zircons from the Late Triassic-Early Jurassic Yinpingshan Formation and the Middle Jurassic Zhangping Formation. The sedimentary environment and provenance distribution characteristics were analyzed and the regional tectonic evolution were integrated for comparative analysis, providing new evidence for the study of tectonic domain transformation of South China Block. The results showed that Yinpingshan Formation formed in a littoral sedimentary environment, with detrital zircon age spectrums displaying peaks at 247 Ma, 422 Ma, and 2 492 Ma. The youngest zircon age was (226.3±1.99) Ma, showing its depositional age to no earlier than the Norian stage of the Late Triassic. Provenance analysis indicated dominant sediment derivation from the southwest, including Jinshajiang-Ailaoshan suture zone, Songma belt, and Hainan Island, exhibiting the structural characteristics of NW-trending folds superimposed by NE-trending folds. In contrast, Zhangping Formation representsed a lacustrine depositional environment, characterized by multi modal detrital zircon age peaks at 173 Ma, 273 Ma, 442 Ma, 781 Ma, 1 858 Ma, and 2 472 Ma. The youngest zircon age was (173.1± 1.56) Ma, suggesting deposition no earlier than the Aalenian stage of the Middle Jurassic. Provenance shifted to a multi-directional supply system, including the eastern Nanling Range, Wuyi Uplift Zone, Jiangnan Orogen, the southeastern coastal magmatic belt, and Hainan Island, showing a NE-trending fold pattern. It demonstrated that Eastern Guangdong Basin was in a transitional stage from the Paleo-Tethyan to Paleo-Pacific tectonic domains during the early Middle Jurassic, combined with the evidence from provenance shifts, facies changes, and differential tectonic features demonstrates.