Abstract: The relationship between the efficacy of wheat aphids control and omethoate concentration and droplets density was very closed. Based on regression analysis, laboratory studies showed that LN90 values were 336.1, 237.6, 208.8 and 115.3 cm-2 respectively, at the omethoate concentration of 1.0, 1.5, 2.0, 3.0 g·L-1 and droplets with 85 μm VMD. The LC 9090 were 29.5, 7.2 and 4.0 g·L-1 respectively, at the droplets density of 26,50 and 102 cm-2. Field experiment exhibited that the efficiency of wheat aphids control and the omethoate concentration of 1.2, 1.6, 2.0, 2.4, 3.2 and 4.0 g·L-1 wasn't highly related when the volume rate was 75 L·hm-2 and 150 L·hm-2 , while the droplets were 173 μm VMD. It was suggested to apply omethoate at a concentration of 2.4 g·L-1 and volume rate of 75 L·hm-2 to control wheat aphids when using motorized mist blower.