The theory of Short-time Fourier Transform and its character are introduced in this paper. The cancellation system of echo interference caused by the coupling of the microphone and the receiver in the table VF system is designed. Using STFT, this system can transfer the necessary signal and the noise signal into the frequency field and the noises can be eliminated through the subtraction of spectrum. The theoretical analysis and estimation methods of subband least square filter based on multichannel echo suppressor are given. This method has stronger self-adaption ability, rapid algorithm convergence and high control accuracy.