The central Tibetan Plateau, situated in the transition zone between Indian monsoon and westerlies, serves as an ideal area for studying the interactions between these two major climate systems. However, only limited research on modern pollen processes in small-scale catchment within this region has constrained the interpretation accuracy of stratigraphic pollen records and the reliability of paleovegetation and paleoclimate reconstructions. This study systematically analyzed the response relationships between modern pollen assemblages and vegetation/climate using 23 surface sediment samples from Lake Cuona and Lake Zigetang, located in the alpine meadow-steppe ecotone of the central plateau. It demonstrates that Cyperaceae (Cy), Poaceae (P), Chenopodiaceae/Amaranthaceae (C), and Artemisia (A) are the dominant components of the regional vegetation, whose pollen assemblage characteristics can effectively distinguish between alpine steppe and meadow. The variations in pollen assemblages across different vegetation types reflect a gradual moisture gradient from meadowdominated to steppe-dominated areas. Principal component analysis (PCA) reveals that the distribution of Cyperaceae, Poaceae, Chenopodiaceae/Amaranthaceae, and Artemisia pollen is primarily controlled by humidity, leading to the establishment of the Cy/(P + A + C) as a robust pollen-based humidity proxy. Application of this proxy to reconstruct regional humidity variations shows: (1) During the early Holocene, relatively humid conditions prevailed in the Lake Zigetang and Ahung Co areas, likely attributable to moisture transport by the Indian monsoon; (2) The middle Holocene witnessed complex dry-wet fluctuations in records from Lake Zigetang, Ngion Co, and Ahung Co, indicating combined influences of monsoon instability and westerly adjustments; (3) The late Holocene was characterized by generally humid conditions, likely resulting from enhanced moisture transport associated with the deepening of westerly circulation into the plateau interior.