The invention discloses an echo 
delay estimating and tracking method. According to the method, the echo 
delay is estimated based on embedding / detection of marking tone in an 
SVM classifier, thereby simplifying the audio 
feature extraction process, meanwhile the position and the amplitude of the embedded marking tone are controlled by using a psychoacoustic model based on 
human ear auditory masking effect so as to avoid auditory 
distortion after embedding and maximally guarantee the integrity and accuracy of original remote signals, in addition, the embedding program and the detection program of the marking tone are alternately executed, for each embedded and detected marking tone, range 
verification is executed, and the echo 
delay is updated according to the detection result, thereby realizing dynamic tracking of the echo delay, compared with the traditional cross-correlation 
algorithm, the echo delay estimating and tracking method has the advantages of high real-time performance, strong robustness and low computational complexity, and the method does not depend on the 
background noise or the independence assumption of the remote 
signal, and has higher reliability.