Abstract: In this paper,a multi thread and modular structure is used to realize the voice-based communication system based on local area network is implemented.Voice signals are sampled and played through PC’s sound card,voice data packet is transmitted through the UDP/IP protocol in the local area network,which can realize point to point two-way real-time voice communication.Besides these tests of quality speech,compression ratio,delay of encoding and decoding,improved or realized other standard speech codec can be added to coding and decoding module of this system and realizing voice communication.Practice shows that the realization of the system can be used for speech signal processing and other related courses of experimental and theoretical teaching.