Abstract: A boundary detection method of Chinese initials and finals is proposed based on the energy distribute and formant structure characteristics.According to this method,the auditory spectrum is first of all got after speech signal passes the Seneff's auditory model,and then based on the spectrum the parameters of all-band energy,low-band energy, spectrum center of gravity,ratio of high and low frequency energy,middle and high energy,etc are chose to describe the energy distribute and formant structure characteristic of different kinds of Chinese initials and finals.Finally,the boundary is determined according to the parameter mutation,and modified using the first envelope difference and simplebased Kullback-Leibler distance.The experimental results show that under 8 kHz sampling frequency,the accuracy is 93.7%for clean speech,above 85.3%for noisy speech with the SNR of 10 dB and above 86.7%for codec speech.