[Objective] To reveal the level, temporal change and reason of drought disasters in Yulin area of Shaanxi Province during the period of 1644-1949.[Methods] Compilation of historical data and wavelet analysis method were used to research relevant problem.[Results] During the 306 years from 1644 to 1949, the drought disasters clearly recorded were 86 times, with average once every 3.6 years. The drought disaster happened 32, 41, 7 and 6 times for mild, middle, great and serious levels, respectively. The distribution of drought disasters in Yulin area during the period of 1644-1949 could be divided into two stages:from 1644 to 1829 with low drought frequency, from 1830 to 1949 with high drought frequency. The continuous drought disasters from 1876 to 1879, 1899 to 1901 and 1928 to 1931 were particularly serious, representing the arid climate event. According to wavelets analysis, it was known that there were mainly 7-year period, 14-year period and 36-year period for drought in Yulin area.[Conclusion] Most of the drought were caused by decreasing of precipitation. In general, precipitation decreased more than 100 mm and 150 mm in the years of great and serious drought, separately. Precipitation that distributed non-uniformly and changed greatly in different years was the main cause of mild and middle drought disasters. Grades and times of drought disasters indicates that climate was more humid during 1644 to 1829 than that during 1830-1949.