Abstract: In this paper, a unified speech and audio coding method that based on Empirical Mode Decomposition (EMD) by exploiting the harmonic structure of input signal was proposed. This coder can achieve a high performance for both speech and audio signals at low and medium bitrates, which cannot be done by the codec with one single analysis model. Prior to the quantization, the EMD was adopted to extract the harmonic components of the input signal, after this, the extracted harmonic signal was modeled and quantized by sinusoidal model and perceptual weighted matching pursuit. For the quantization residual of harmonic signal, the dithered lattice vector quantization was used to improve the subjective quality. Finally, both the objective PESQ/PEAQ results and subjective A/B listening tests show that the proposed coder outperforms the ITU-T G.722.1 and G.722.2 codec.