In order to analyze the annual water runoff distribution and the changing particularities of the Urumqi River, along with the quantitative estimation of the effects of the temperature and precipitation on the water runoff, this paper wishes to identify the variable characteristics and trends of the temperature, precipitation and the water runoff in the mountainous areas of the Urumqi River basin since 1993. This paper also intends to disclose thetime-lag effects between the runoff and the precipitation by examining the trends of their PCP and PCD by using the accumulated temperature to fit the relationship between the temperature and the runoff during the spring melting stage. Itis just on the basis of all the aforementioned aspects, this paper has introduced a gray correlation model and correlational analysis method to our study of the mutual relation among the runoff, the temperature, and the precipitation. Theresults of our correlational and inter-relational investigation and analysis demonstrate that both of the precipitation and temperature have direct and indirect effects on the water runoff in annual variation terms respectively, though there may exist a lot of mutual relevance among themselves. What is more, even though the distribution of the annual runoff and precipitation is uneven, it can still be predicted that their PCPs may all come up in June, in spite of there beinga lag effect between them. In addition, though the distribution of temperaturewithin a year or in the melting period of a year appears in a parabola, the relation between the temperature and the runoff remains exponential with a high fitting degree. The results of a Grey correlation analysis and a more careful related correlation analysis turn to be almost consistent, i.e. the effect of precipitation on the runoff can usually be obviously higher than that of the temperature. The description of the response relationship between the runoff and the climate proves to have been deepening especially in the arid areas of Urumqi River andits branches. Thus, it can be concluded that through the research of the UrumqiRiver, the paper has been trying to make clear the annual changing characteristics and the influencing factors of the various runoff, which can provide a certain theoretical support for the watershed management and further possibilities todredge the said arid areas in the river reach in the future.