Abstract: Arithmetic coded trellis coded quantization (actcq) is the combination of trellis coded quantization (tcq) and arithmetic coding (AC). An improved G.719 audio codec was proposed in this paper by applying ACTCQ to the G.719 audio codec. Both the objective and subjective experimental results show that, compared with the G.719 audio codec, the improved codec not only reduces the coding rate, but also obviously improves the reconstructed audio quality.