In this paper, the content-based retrieval of one-singer audio example based on MP3 (MPEG 1 layer III) digital music archive is considered. In our proposed method, the Sub-Band Coefficients (SBC) in a MP3 frame is used for feature extraction. Both Quantization-Tree indexing (QT) approach and the Mel-Frequency Subband Coefficients (MFSCs) approach are proposed for indexing on MP3 objects. Finally, a Melody-Line contour comparison method is used to measure the similarity between MP3 objects. Evaluations on a content-based MP3 retrieval system are performed. Experimental results show that our proposed approach can perform good performance and high accuracy. At least 95.9% of accuracy can be achieved at the top-1 retrieval result.