<p>The Qinghai-Tibet Plateau spans a vast area with highly complex natural conditions, making ecosystem classification and the delineation of field boundaries challenging. Ongoing climate warming has intensified glacial melting and thawing of permafrost, further complicating surface hydrological processes. The frequent alternations of redox conditions driven by soil water saturation make it difficult to distinguish the boundaries between wetlands and grasslands. Consequently, traditional wetland definitions and classification frameworks are inadequate for depicting the spatiotemporal patterns of alpine wetlands on the plateau, constraining a deeper understanding of the ecosystems. In this study, a novel multilevel framework for wetland classification is proposed. By integrating long-time-series Landsat 5/7/8 images, multisource environmental data, and field investigations, a 30-m annual dataset of alpine wetlands distribution on the plateau for 2000–2020 was constructed on the basis of a cloud computing platform to analyze spatiotemporal patterns and their driving factors. The results indicate that the overall classification accuracy is 0.92, which is highly consistent with that of high-resolution images. Over the past two decades, the total area of alpine wetlands on the plateau ranged from approximately 9.0×10⁴ to 1.2×10⁵ km², accounting for approximately 4%–5% of the total area. Among these, lakes, rivers, marshes, and wet meadows accounted for 49%–64%, 0.7%–1%, 7%–12%, and 28%–39% of the total wetland area, respectively. Spatially, lakes were distributed mainly on the Qiangtang Plateau, marshes were concentrated in Zoige, and wet meadows were located primarily adjacent to marshes or along river and lake shorelines. Temporal analysis revealed an overall expansion trend of alpine wetlands, with the highest expansion rate observed in wet meadows (0.6×10³ km² year⁻¹), followed by lakes, whereas marshes experienced initial contraction and subsequent expansion. Climate warming, increased precipitation, active layer thickening, and reduced snow cover may contribute to wetland expansion. Connectivity modulates wetland responses to environmental changes, with wetlands in low-connectivity regions being more sensitive to environmental variations, whereas those in high-connectivity regions exhibit lower sensitivity. This study elucidates the spatiotemporal patterns of alpine wetlands on the Qinghai-Tibet Plateau and reveals that connectivity modulates wetland sensitivity to environmental changes, providing a scientific basis for wetland conservation and management.</p>