[Background] Surface runoff of cold and arid regions is particularly sensitive to climate change, climate factors such as precipitation, potential evaporation, temperature of the slight change, can cause the change of surface runoff system. At present, the impacts of climate change on runoff,mainly were focused on single statistical analysis on the impact of meteorological factors on runoff, and ignoring the mutual influences among the impact factors. In fact, the complicated relationship between meteorological factors is multivariate. [Methods] Taking Xilin River basin as research target, the relationship between runoff and varied factors of precipitation, average temperature, highest temperature,lowest temperature, sunshine duration, potential evaporation and effective accumulated temperature were studied on yearly time-scale and seasonally time-scale by the method of correlation, partial correlation and path analysis, and their direct and indirect impacts on the runoff were determined by path analysis. The data were obtained from 4 national weather stations in 1960—2010, one weather station is Xilinhot station in the area, and other three are Abaga, Linxi and Keshiketeng stations near the area. The runoff data were from Xilinhot hydrometric station measured in 1960—2010. [Results] There were two obvious flood seasons of runoff process in Xilin River, they were April spring flood and the summer flood in July. The correlations between runoff and factors of sunshine duration, annual average temperature, minimum temperature and maximum temperature in yearly time-scale were insignificant. Both the direct effects and the indirect effects through other factors on the runoff were also little, thus they were not the main meteorological driving factors affecting the runoff. The correlation between runoff and precipitation, potential evaporation, effective accumulated temperature was highly significant, and the direct effects of them on runoff was high, therefore they were the main factors affecting on the runoff in yearly time-scale.On the seasonally time-scale, the top 3 factors impacting runoff were also potential evaporation, rainfall and effective accumulated temperature. Different weather factors contributed differently to the runoff of Xilin River in different seasons; the main control factor was effective accumulated temperature in spring,while in summer and autumn the main atmosphere control factor was precipitation. Due to the influence of seasonal frozen soil, the correlation coefficient and direct path coefficient between runoff and accumulated temperature was significantly higher than the those between runoff and temperature, especially in the spring, the direct path coefficient between runoff and accumulated temperature even was higher than that between runoff and precipitation. [Conclusions] The direct correlation between runoff and atmospheric variables can be determined by path analysis in the study of relative importance of each climatic factor, thereby determining the impacts of those factors on runoff change and providing a reliable basis for decision-making.