A good correlation exists between drought and underground general circulation. Based on about the data of drought of recent 50 years,there are 4 types in total of who create drought. The first is large underground cold vortex,the second is large negative area anomaly of inter-monthly (inter-seasonal) underground temperature of 3.2 m depths. The third is serious drought before strong earthquakes (drought-earthquake relationships). The last one is region that cold vortex stayed after a macroseism. Further more,we found that cold vortexes slowly move because of its long wavelength,and droughts result from cold vortexes are usually more serious. Negative anomaly of underground temperature of 3.2 m depths shows a weakened thermal process,it can be seen a signal to predict rainless the next month. After all,both serious droughts and floods of China are related to strong earthquake.