This paper demonstrates a novel electronic nose (e-nose) system for volatile organic compounds (VOCs) detections which is composed of three high-Q piezotransduced single-crystal silicon bulk acoustic resonators (PSBARs) and functionalized with different self-assembled monolayers (SAMs). The different sensitivities of the PSBARs to VOCs are utilized to constitute unique identification codes for IPA, ethanol, hexane and heptane detections, and successfully realizing discriminations of different VOCs. Besides, ethanol vapor with concentration as low as 50 ppm has been successfully measured by SAM modified PSBAR.