The basic principles and ceding techniques of the waveform inteoplation for speech analysis and reconstruction are described in this paper. The practical architecture for a 2 .4kbps vocalerbased on waveform interpolation is also given. The redundancy of the pitch-cycle waveform in residual signal is removed effectively by characteristic waveforms extraction and voiced/unvoiced Separation. High quality reconstructed speech can be obtained at 2 .4kbps bit rate.