The invention provides a circuit for extracting duty cycle information of a digital pulse signal, mainly solving the problems of unstable working and low calculation accuracy in existing method for extracting duty cycle information of the digital pulse signal. The method for extracting duty cycle information of the digital pulse signal is applied to pulse signals that have the frequency range of 1-1000Hz, voltage of TTL level and duty cycle of 50%-99%. Firstly, an input signal is converted into two paths of direct current signals through two paths of integral circuits with opposite input phases; clutter is filtered through a lowpass filtering circuit; and finally, the direct current signal with high value is selected from the two paths of direct current signals and is sent out. According to the circuit for extracting duty cycle information of the digital pulse signal, it is ensured that the output value of the duty cycle of waveform corresponding level is always greater than 50%, so that real-time, reliable and stable direct current output is provided for a rear end voltage acquisition circuit.