Abstract: Through an analysis of meteorological data from 1980 to 2012 of Zhumadian City in Henan Province， simultaneously taking consideration of winter wheat’s sensitive degree to moisture in different stages，effective rainfall， and the influence of soil water on winter wheat yield，we constructed a series of drought and flood indexes suitable for Zhumadian’s winter wheat on the basis of relative humidity index. Besides，rating standards of drought and flood indexes were also set according to lots of materials including China meteorological disasters ceremony of Henan volume， agricultural meteorology ten-day reports and agricultural disaster ten-day reports data and so on. After a test for indicators set above，we found that these indicators could reflect winter wheat’s drought and flood correctly. Finally， we also studied the characteristics of drought and flood of winter wheat. Results showed that to winter wheat，drought appeared more during 1980-2012，and almost no severe drought happened. Moreover，disasters from turning green to spiking were all droughts，and flood occurred occasionally from spiking to maturation.