Spatio-temporal change characteristics of the persistent meteorological and hydrological drought in Yunnan from 2009 to 2014 were analyzed based on Dai Palmer drought severity index(Dai-PDSI)and streamflow drought index(SDI). The causes of persistent drought were investigated based on the NCAR/NCEP reanalysis data from various perspectives including: the West Pacific subtropical high, Tibetan high, Southern Branch Trough, tropospheric vertical motion, and vertical distribution of water vapor. The results showed that the persistent drought from 2009 to 2014 was the longest drought in Yunnan since 1961. The driest period was from October, 2009 to September, 2010, and summer and winter were two driest seasons. The drought in the east of Yunnan was the heaviest and the drought in the southeastern part was slightly light. Hydrologic drought was accompanied by meteorological drought. The heaviest hydrological drought was in Jinsha River and Nanpan River. Secondary hydrological drought occurred in the Lancang River. In terms of strength, hydrologic drought is weaker than meteorological drought. In summer, the atmosphere over Yunnan was controlled continuously by downward flow due to that the West Pacific subtropical high was stronger and westward and the Tibetan high center was westward. In winter, the Southern Branch Trough was weak and could not help to guide the water vapor from Bengal Bay to Yunnan. In other seasons, downward flow prevailed and water vapor was seriously shortage in troposphere.