A　bandwidth　extension　method　based　on　audio　classification　was　proposed.　Time　series　of　audio　signals　were　classified　into　four　types　based　on　recurrence　plot　and　recurrence　quantification　analysis,　and　the　fine　spectrums　were　recovered　by　taking　advantage　of　four　methods　respectively.　In　addition,　the　spectrum　envelope　and　energy　gain　were　adjusted　by　Gaussian　mixture　model　and　codebook　mapping　on　the　basis　of　soft　decision　respectively.　Subjective　and　objective　testing　results　indicate　that　the　proposed　method　has　good　quality　compared　with　conventional　blind　bandwidth　extension　methods,　and　the　performance　of　ITU-T　G.722.1　codec　with　the　proposed　algorithm　is　better　than　that　of　G.722.1C　codec　at　the　same　bit　rate.