Abstract: Based on the streamflow observation data of the Petropavlovsk hydrological station of the Ishim River in northern Kazakhstan from 1933 to 2016 and meteorological data of the grid points in the basin,the streamflow variation of the Ishim River and its main driving factors in the context of climate change were explored by using the linear trend method,Mann-Kendall test,correlation census method and cumulative slope rate of change comparison method.The results show that:（1）Temperature and precipitation in the Ishim River basin have been increasing in the last 84 years,and the increasing trend is more obvious after the 1970s.（2）The streamflow of the Ishim River is unevenly distributed within the year,and the interannual streamflow variation generally shows a decreasing trend,but the trend is not apparent.（3）The streamflow of Ishim River is influenced by precipitation and temperature in the basin,among which precipitation has the strongest correlation with streamflow,and the change of precipitation has a lag on streamflow recharge.The temperature in June-September has a more significant influence on streamflow in the same period.（4）The contribution of climate change to the decrease of streamflow are 16.09%and 44.83%in the T₁ period （1969-1996）and the T₂ period （1997-2016）compared with the T period （1933-1968）,while the contribution of human activities to the decrease of streamflow are 83.91%and 55.17%,respectively.Anthropogenic factors such as development and utilization of water resources in the basin,variations in population size and land use patterns largely influence the streamflow of the Ishim River.