A wireless charging system with double detecting circuits comprises a detecting circuit connected to an inductive loop to detect the induced electric field of the inductive loop; an auxiliary detection circuit connected to a power loop to detect the induced electric field of the power loop, wherein when the waveform detected by the detecting circuit is not applicable, it is replaced by the waveform detected by the auxiliary detecting circuit in order to determine the condition of the electrical receiver device and thus adjust the output to the inductive loop from the power loop.