Abstract: Based on the monthly precipitation data observed by 57 meteorological stations in the Qinling Mountains during the period from 1961 to 2009, this paper analyzes the temporal and spatial trends of drought and flood in the north and south of the Qinling Mountains and the response of regional drought index and Z index to global climate change using mainly the MK mutation test, wavelet analysis and Kriging interpolation. The conclusions are as follow: (1) Climate trend rate of average annual temperature in Guanzhong was higher than that in south Shaanxi Province, and the abrupt change of average annual temperature occurred in 1996 in these two areas; (2) In recent 49 years, the warmingdrying trend, spring drought and summer flood in Guanzhong were more significant than that in south Shaanxi Province. The proportion of severe drought increased in both the north and south of the Qinling Mountains, but that of partial flood decreased after the abrupt change of average annual temperature. There were the 3-4year and 22-27year periodicities of drought and flood in Guanzhong, but 3-4year and 24-30year ones in south Shaanxi Province, and these periodicities corresponded to the occurrence of El Nino and solar activity; (3) Frequency of severe drought in south Shaanxi Province was higher than that in Guanzhong. The distribution regularity of annual severe flood frequency was not strong, and the centers were scattered. Frequency of drought and flood was distributed in a latitudinal way in winter but in a longitudinal way in other seasons.

Key words: climate change, drought, spatio temporal distribution, periodic variations, El Nino, the Qinling Mountains, Shaanxi Province