Abstract:By using monthly precipitation data of 30 meteorological stations within the apple production area in Shaanxi Province from 1961 to 2010, the standardized precipitation index SPI3, SPI6, SPI9 and SPI12 were calculated. Results show that annual SPI12, spring summer autumn SPI9 and autumn SPI3 have a significant linear downward trend (P<0.05) and drought intensity tends to increase. The frequency of light drought, mild drought, severe drought and extreme drought in the study area are 16%, 6%, 4% and 0% correspondingly. Kriging interpolation method is used to draw drought frequency distribution map based on SPI value of the stations in the study area. The spatial distribution of annual drought frequency shows that four high drought frequency areas distribute with certain intervals from south to north and the drought frequency in Guanzhong Area is the highest. The spatial distribution of spring summer autumn drought frequency has a similar regulation with the frequency of annual drought. The distribution of winter spring drought frequency generally shows the trend of being higher in south than in north. The distribution of winter spring drought frequency shows that the frequency in middle is higher than in the both sides. The drought frequency in Guanzhong Area is the highest in spring, while that in the east of Weibei Area is the highest in the other seasons. In addition, 76.4% apple orchards do not have irrigation facilities, so this research is of some significance for establishing targeted drought relief measures and emergency preplans.