This paper mainly studies the variation characteristics of hydrologic and meteorological elements in the Weihe river source area, and further analyzes the relationship between the various elements. The variation trend of hydrologic and meteorological elements in the Weihe river source area was tested by using the Handel rank correlation, Barmen rank correlation, and linear trend regression test. The mutation year was found out by using the M - K test, and the influence degree of rainfall and evaporation on the runoff in the different stages was analyzed by using multiple linear regression analysis. In the past 30 years, the annual precipitation and seasonal precipitation did not show a significant decreasing trend; and the annual evaporation and the evaporation in spring and summer showed a significant increasing trend; annual runoff and the runoff in summer showed a significant decreasing trend; the runoff in winter did not show a significant increasing trend. Annual precipitation and annual runoff occurred significant mutations in 1993, and annual evaporation occurred significant mutations in 1990. The annual runoff change is mainly affected by the change of precipitation from 1981 to 1993, and the change of annual runoff is mainly affected by the change of evaporation from 1994 to 2010.