To　reduce　the　computational　complexity　of　characteristic　waveform　(CW)　representation　and　alignment,　improved　algorithms　for　CW　representation　and　CW　alignment　are　proposed　by　applying　fast　Fourier　transform,　cubic　B-spline　interpolation　and　period　extension.　The　improved　algorithms　are　correspondingly　independent,　and　their　complexity　is　reduced　from　43.252　million　operations　per　second　to　9.178　million　operations　per　second.　The　experimental　results　show　that　the　improved　algorithms　have　greatly　reduced　the　computational　complexity　and　kept　the　same　speech　quality　as　original　coder.