It adopts the microwave as a kind of energy. When the microwave interaction with the material molecular, it occurs molecular polarization, orientation, friction, collision. Then the materials absorb microwave energy and produce heating. It is the material itself absorbing microwave heating from internal to external, at the same time bacterias and worms are killed by the microwave. Different materials have different microwave absorbing capacity, so the heating effects are also not identical, this mainly depends on the dielectric loss of material.