A 13-m long sediment core from Borsog Bay of Lake Khuvsgul, northern Mongolia records hydro-environmental changes during the past 10000 years; three rapid environmental changes (ca. 2700 a BP, ca. 6000 a BP and ca. 8000 a BP based on14C dates of organic carbon materials) are detected in depth proifles of sediment physical properties. Temporal changes in the physical properties of the core (grain size, grain density and water content) also suggest three periods of large discharge from outside and three periods of stable input (200~500 cm, 800~980 cm and 1050~1200 cm). The sedimentation rates in the stable period are 0.102 cm·a–1, 0.085 cm·a–1 and 0.139 cm·a–1, respectively. The periods of large discharge likely correspond to the intervals of the three rapid environmental changes, indicating that there were three rapid and high discharge periods related to melt water and/or heavy rainfall during the past 10000 years in this region. The analytical results also show that the physical properties are valuable in reconstructing past hydro-geomorphological lfuctuations in the lake-catchment system.