Abstract: A wireless charging system, a wireless power transmitter, and a wireless transmitting method are provided. The method includes generating a pulse width modulation signal having an operating frequency according to a parameter, transmitting a power signal according to the pulse width modulation signal, generating a sampling frequency according to the operating frequency, obtaining power adjusting information from a transmission coil according to the sampling frequency, and adjusting the parameter according to the power adjusting information. The sampling frequency is the product of the operating frequency and a multiple, and the multiple is the summation of an offset and a positive integer. The offset is in the range of 0.25 to 0.75.