Since the late Permian,influenced by theIndosinian orogeny and the Emeishan basalt eruption, the sediment sources and sediment patterns have changed significantlyin the southwest margin of the upper Yangtze, which stimulated heated discussion in academia. Therefore, in this paper, considering the detrital rocks from the Lower Triassic Feixianguan Formation in the Daibu area of Southwest Upper Yangtzeas an example, constraints on thesource rock properties, material provenance, sedimentation and tectonic environment background usingpetrography, petrogeochemistry, and zircon U- Pb chronology are provided. The maturity of the detrital rocksfrom the Feixianguan Formation is low, and the weathering degree of the rocks ismedium, the source region has experienced continuous tectonic uplift and denudation, and deposition occurredin the oxidative sedimentary environment of the shallow- littoral faciesin the southwestern margin of the Yangtze in the Early Triassic. The U- Pb age of zircon in this paper is mainly concentrated at 257±29 Ma, which is consistent with the main eruption time of Emeishan basalt in Late Permian.The petrogeochemical characteristics of the detrital rocks are highly consistent withthe Emeishan high- Ti basalt, indicating that the mainsource area of the Feixianguan Formation is the near- source Emeishan igneous province, the source rock is mainly the Emeishan high- Ti basalt which formed in anintraplate extensional environment, and during the basaltic magma upwellinga small amount of ancient crystalline basement components of the Yangtze block were mixed in. Furthermore, the Kangdian ancient land and the Yangtze craton also provided part of the sediment sources, mainly the magmatic rocks which formed under the background of the Rodinia supercontinentconvergenceand breakup. Chronological evidence shows that the Rodinia supercontinent convergence and breakup events have a good response to the sediment sources in the study area,which provides an important reference basis for the timeconstraints of global Rodinia supercontinent convergence and breakup events.