A system and method for promoting immunity of animals or human, which comprises an energy wave generator has an energy wave's frequency control mode. The energy wave's frequency control mode includes multiple controls for acting the energy wave generator to generate and emit energy waves each with a corresponding energy density. The energy density is calculated by a corresponding base frequency, a sweep bandwidth of the corresponding base frequency, an emission rate and a total time of emission in a duty cycle, so that the energy waves with the corresponding energy densities effecting on the body of animals or human to promote immunity of animals or human.