Abstract: In order to study the insecticidal effect of microwave irradiation on Ephestia elutella, and to evaluate the application value and economic threshold of microwave control of E. elutella, the eggs, larvae and pupae of E. elutella were treated with a self-made microwave equipment with different power and time. The results showed that when the microwave power and treatment time were 4 kW, 220 s, 5 kW, 190 s, and 6 kW, 170 s, all the eggs, larvae and pupae were killed. At different larval densities, the indirect economic losses caused by larvae of E. elutella were much higher than the direct economic losses. The economic loss rate per larva was 0.40%, and the economic threshold was 2.95 larvae per kilogram tobacco leaves when using the microwave equipment. Therefore, when the insect population density was more than 2.95 larvae/kg, it was of practical significance to use microwave to control E. elutella. The optimal microwave power and treatment time were 6 kW, 170 s.