This paper presents the optimization of dielectric heating by using capacitor copper plate material. It has dimension of 50x50 mm. and the distance between plates is 3 mm. This work is used for preheating of insect and pests. Considering the RLC resonance circuit and the power per heating area, the rice weevils are used for sample dielectric. While the power transfer is varied from 10 - 80 watt and resonance frequency at 65 MHz for analysis, the rice weevils are died when the power transfer are more than 70 watt in 1 second. Moreover, It the power transfer is decrease, the period of time is increase. Approximate 10 watt of power transfer, the plate copper has less power so the rice weevils are breaking. Therefore, the power transfer has an effect on the heating area, which is the relation of the fast time.