Abstract: To unravel the sedimentary evolution and controlling mechanisms of the Pinghu Formation in the central Western Slope of the Xihu Sag, East China Shelf Basin, we used an integrated stratigraphic method in combination with conventional methods of sequence stratigraphy and multi-source geological data analysis. Through systematic interpretation of seismic profiles, well logging data, and core observations, we established a high-resolution sequence stratigraphic framework and investigated the sedimentary system evolution. Results show that: the Pinghu Formation in the study area could be subdivided into five third-order sequences based on transgressive-regressive cycle identification, providing a robust chronostratigraphic framework for basin analysis. Four sedimentary systems were recognized through facies analysis: lagoon-barrier island complex, tidal flat system, shallow marine-coastal system, and deltaic system. These systems comprise distinct subfacies including delta front, tidal flat, barrier island, lagoon, and coastal deposits, showing systematic spatial-temporal variations across sequences. The evolutionary patterns of depositional systems demonstrate a progressive transition from fluvial-dominated to tide-dominated and ultimately wave-dominated systems along the terrestrial-marine transect. This transition was governed by the interplay between relative sea-level changes and inherited paleotopographic features, and the sequence architecture shows distinct responses to different forcing mechanisms. This research enhanced understanding of sedimentary evolution in the Pinghu Formation of Xihu Sag and provided a foundational support for studying hydrocarbon accumulation conditions and sandbody distribution in the western slope zone.