In order to improve the utilization of speech communication transmission bandwidth, a discontinuous transmission method based on hybrid excitation linear predictive vocoder is proposed. Using the voice activation detection algorithm to distinguish the received voice signal into voice frames and silent frames, a transition frame is introduced during the conversion from voice frames to silent frames. The voice frames and transition frames are encoded using normal bit rates, while the silent frames are encoded as silence descriptor (SID) frames using lower bit rates, and SID frames are sent in a discontinuous manner, The transmission frequency of SID frames is adaptively adjusted based on the fluctuation of the characteristic parameters of background noise in silent frames. Simulation experiments show that this method has good adaptability when transmitting silent segment signals, and the synthesized background noise has good comfort and continuity in subjective auditory perception.