The invention discloses a method for extracting a pitch period of telephone wire quality voice. The method comprises the following steps of: nonlinearly processing primary voice, and calculating a first time domain self-correlation function of primary voice and a second time domain self-correlation function of nonlinearly processed voice; integrating the first time domain self-correlation function with the second time domain self-correlation function to obtain a third time domain self-correlation function; calculating a long time pitch period of each frame in the primary voice and amending the third time domain self-correlation function; performing LPC inverse filtering of the primary voice to obtain residual signals, performing FFT (Fast Fourier Transform Algorithm) conversion, and calculating a frequency domain self-correlation function according to conversion results; according to the third time domain self-correlation function and the frequency domain self-correlation function, calculating time domain weight and frequency domain weight of a pitch period candidate value and further obtaining the ultimate weight; according to the ultimate weight, performing route planning to determine a final pitch period value. When the telephone wire quality voice is extracted by the method, the accuracy is high.