A novel audio compression method called Harmonic Structure Quad Tree was presented. The method employs a bitplane based quantization-encoding method called Concurrent Encoding in Hierarchical Tree to encode MDCT coefficients of the overlapping audio frames. Scalability is easily achieved by discarding the tailing bits at any position of the bit-stream as long as head information is preserved. In this article, an embedded harmonic structure reconstruction method is proposed to predict and restore the coefficients missed during the encoding process. The proposed method is compared favorably to the popular MP3 coder in both pop and classic audio programs. No psychoacoustic model is used. The computation complexity and the coding table size are much smaller compared to those of MP3 coder.