The long-term response of coastal environments to sea-level fluctuations and climatic variability during the Late Quaternary remains poorly constrained in the Hangzhou Bay (HZB) region due to limited continuous records with reliable chronology. Here we present a multi-proxy investigation of the 145.52 m-long sediment core ZH02 recovered from the Zhejiang coastal plain. The study integrates pollen and spore assemblages with foraminiferal and ostracod records, together with accelerator mass spectrometry (AMS) radiocarbon dating, magnetic susceptibility (MS), and grain-size analyses to reconstruct environmental evolution associated with marine transgression along the East China Sea (ECS) margin. An improved chronological framework extending to ~105 ka was established through spectral analysis and age modelling, providing a robust basis for evaluating long-term environmental changes. Variations in MS and sediment characteristics reflect shifts in sediment provenance and hydrodynamic conditions, and effectively capture transitions between terrestrial and marine depositional environments. In total, 57 pollen and spore taxa were identified, accompanied by diagnostic planktonic and benthic foraminifera and ostracod assemblages, indicating repeated alternations between continental and shallow-marine settings. Based on lithological characteristics, microfossil assemblages, and chronological constraints, the sediment sequence is divided into three environmental phases: Phase I (145.52–79.02 m; 104.6–68.77 ka), Phase II (79.02–27.8 m; 68.77–10.05 ka), and Phase III (27.8–0.50 m; 10.05–1.63 ka). Periods characterized by enhanced marine influence and relatively warm–humid environmental conditions correspond to major regional transgressive events, including the Jiangyin (~84 ka), Gehu (~51 ka), and Zhejiang (~8.5 ka) transgressions. In contrast, intervals centred at ~88 ka, ~61.9 ka, and 25.3–21.1 ka reflect reduced marine influence and more terrestrial conditions associated with colder and drier climatic phases. Among these events, the Gehu transgression during MIS 3 represents the most pronounced marine incursion recorded in the core, whereas the Zhejiang transgression during MIS 1 shows a moderate marine influence and the Jiangyin transgression during MIS 5 appears comparatively weaker. These results reveal complex transgressive–regressive dynamics in the Hangzhou Bay coastal system, driven by interactions among regional sea-level change, sediment supply, geomorphological setting, and climatic variability. The ZH02 record therefore provides new insights into Late Quaternary coastal environmental evolution and marine transgression processes along the East China Sea shelf.