With　a　mixture　Gaussian　mapping　method　for　speech　spectral　envelope　transformation,　a　Mandarin　tone　codebook　mapping　algorithm　for　the　pitch　conversion　is　proposed　to　improve　the　preference　for　target　characteristics　in　the　converted　speech.　The　syllable　pitch　contours　are　first　extracted　from　the　source　and　target　speech,　and　preprocessing　and　clustering　operations　are　performed.　A　tone　mapping　codebook　is　obtained　by　associating　the　source　code-book　with　the　target　one.　Voice　conversion　experiments　are　performed　to　evaluate　the　tone　codebook　mapping　algorithm.　Results　show　that　the　method　gives　a　good　mapping　between　the　source　and　target　pitches,　and　improves　the　performance　of　voice　conversion　for　Mandarin　speech.