In　this　paper,　a　2　kb/s　Waveform　Interpolation　speech　coding　scheme　is　described　based　on　the　EWI　speech　coding　model　proposed　by　Oded　Gottesman.　The　algorithm　produces　high　quality　speech　with　the　improved　quantization　methods　for　encoder　parameters.　In　this　2kb/s　Enhanced　Waveform　Interpolation　speech　coding,　the　rapidly　evolving　waveform　(REW)　magnitude　is　represented　by　the　2-D　parametric　surface　and　quantized　with　the　analysis-by-synthesis　(A-b-S)　approach,　the　slowly　evolving　waveform　(SEW)　is　optimized　and　quantized　with　A-b-S　method　as　well,　and　the　power　is　quantized　with　switched-predictive　A-b-S　method.　The　computer　simulation　results　and　subjective　tests　show　that　the　coded　speech　quality　exceeds　that　of　federal　standard　2.4　kb/s　MELP　coder　greatly.