The present invention discloses a demodulating method for a demodulating circuit. The demodulating method comprises a step of utilizing a wave-shaping voltage step-down circuit to perform a wave-shaping process for a modulating input signal. A separate circuit of modulating input signal is filtering data zero of the modulating input signal and reserving data one of the modulating input signal. A triggering circuit of data recover is used to start the count of data span, until the data count is completed. A data recover circuit is used to recover the data. |