Based on homogeneous temeperature, precipitation and the Palmer Drought Severity Index (PDSI) data between 1958 and 2007 of 194 stations in China, quantitative measure of impact of global warming and precipitation variation on the formation of drought in China is made through a statistical model. Dividing China into eight regions, we analyzed the importance of global warming and precipitation variations in each region respectively. Under the background of global warming, the trend of drought in north China still persists. The most probable region of drought in the next five years shows a tendendy of expansion in north China, especially in the direction to the south. Decreased precipitation is still the key factor in drought formation in most regions. However, in the north, northeast and east-northwest China, global warming plays a bigger role in drought formation.