From the autumn of 2009 to the spring of 2010, a serious drought occurred in Zunyi, The drought has caused severe damage and loss to agriculture, forestry, drinking water, hydraulic power, etc. This paper analyzes the elements of weather during the drought. From September 2009 to March 2010, total rainfall was less than half of the annual average amount of the past years. With comparison with winter droughts of the past years, meteorological elements such as rainfall in most parts of the city reached an all-time low. It is believed that the drought from 2009 to 2010 has been the most serious drought from autumn to spring successively since the city had meteorological record. The drought took place on the basis of the little rainfall in summer of 2009, and thus its impact is quite serious. The general circulation and the transfer of water vapor characteristic in arid period are discussed. It is believed that the continuous strong subtropical pressure, the weak cold air influence and the difference of the transfer of water vapor create the arid main meteorological origin.