The change of Arctic river runoff could affect the sea ice thermal process and ocean thermohaline circulation. Based on the temperature， precipitation and runoff data from 1936 to 2017 provided by Global Precipitation Climatology Centre（GPCC）and Russian Hydro-Meteorological Services， the variation characteristics of climate and runoff in the Lena River Basin of Arctic over the past 80 years were analyzed， and the impacts of climate change on runoff were explored. The results suggested that the air temperature， precipitation and runoff all showed an increasing trend， with rates of 0.18 ℃·（10a）-1， 4.7 mm·（10a）-1 and 399 m3·s-1·（10a）-1， respectively. The runoff showed an upward trend in all seasons， especially in spring and winter. The increase of spring runoff was mainly caused by the acceleration of snow cover melting due to the higher temperature， followed by the replenishment of spring precipitation. The main reason for the increase of summer and autumn runoff was the contribution of increasing precipitation， higher temperature increased evaporation and reduced runoff. The increase of runoff in winter was due to the degradation of permafrost or thickening of the active layer as temperature rising， which promoted more frozen water to enter the runoff process， resulting in the increase of runoff.

Keywords： Arctic ; Lena River Basin ; temperature change ; precipitation change ; runoff change