A wireless power transmission and charging system, and a communication method of the wireless power transmission and charging system are provided. In one embodiment, a resonance frequency control method of a wireless power transmitter may include: generating communication power used for communication in a plurality of target devices using a reference resonance frequency; transmitting communication power to the plurality of target devices; transmitting charging power to the plurality of target devices; and adjusting the reference resonance frequency based on a reflected wave of the charging power, the amount of power received by one or more of the target devices, the amount of the charging power, the transmission efficiency of the charging power, or any combination thereof.