This　paper　proposes　a　multi-layer　super　-widebandembedded　speech　and　audio　coding　algorithm　extending　bit　rates　from　36　to　64　kb/s　on　the　basis　of　ITU-T　Recommendation　G.729.1　with　a　multi-stage　coding　structure.　This　codec　consists　of　three　embedded　stages:　G.729.1　wideband　coding　operating　in　the　range　from　8　to　32　kb/s,　modified　Modulated　LappedTransform　(MLT)　coding　of　the　band　(7-14　kHz)　at　36,　40　&　48　kb/s　and　MDCT　transform　coding　for　wideband　residual　signal　at　56　and　64　kb/s.　In　addition,　some　methods　are　proposed　in　transform　coding　according　to　perception　significance.　The　objective　and　subjective　listening　tests　show　that　this　codec　has　good　performance　compared　with　reference　codec.