Abstract <p>This study aims to enhance the understanding of climatic evolution by quantitatively reconstructing the paleoglacial coverage and paleo-equilibrium line altitude (ELA) in the Turgen–Asgat Catchment during the marine isotope stage (MIS) 3b and the global last glacial maximum (gLGM), based on glacial geomorphology and ¹⁰Be exposure dating. The coupled 2D ice flow model and precipitation–temperature relationship model (P–T model) were employed in this reconstruction. The results indicate that during marine isotope stage 3b (MIS 3b), the total paleoglacial area in this basin reached 189.9 km² with an ice volume of 43.2 km³, and the ELA stood at 2846.5 m (a.s.l.). By the gLGM, the paleoglacial area had decreased by 6.4%, ice volume by 3.9%, while the ELA rose by 36.6 m. Furthermore, after combining proxy data such as pollen records and treeline altitudes (in m a.s.l.) from the surrounding areas, it was found that precipitation in the study area during MIS 3b was 90–110% of modern levels, with mean summer temperatures 2.9–2.6°C lower than today’s; during the gLGM, precipitation was ~40–50% of modern levels, with summer temperatures 4.4–2.8°C lower than the present day. By comparing these reconstructed results with modern climatic conditions in neighbouring regions, it was inferred that factors such as topography and the monsoonal environment may have influenced the degree of climatic variation.</p> Research Highlights <p><OrderedList> <ListItem> <ItemNumber>(i)</ItemNumber> <ItemContent> <p>This study reconstructs the scale of palaeoglacier in the Turgen–Asgat Catchment of the Altai Mountains in Mongolia, enriching the evolutionary history of high-latitude glaciers in the high-altitude Asia region. It also enriches the climate indices of the Altai region based on glacier evolution.</p> </ItemContent> </ListItem> </OrderedList></p>