年來隨著MP3的誕生趨勢，許多P2P平台紛紛崛起，也促進新型數位音樂產業的誕生。像是Apple推出的iPod風靡全球，但是在這些成功的背後卻隱含相當大的危機-非法MP3數位音樂下載氾濫。即使近年來出現了像是iTunes這樣的合法付費線上音樂商店，還是一樣無法保證能夠削減非法數位音樂問題的嚴重性。本論文即是針對MP3這種利於傳輸的數位音樂格式，如何進行線上即時傳輸偵測的相關技術加以探討，並提出抑制非法MP3的流竄來貫徹智慧財產權的理念。在本文中我們提出一套MP3音樂下載之偵測系統，藉由網路封包的攔截以及解碼，進而擷取其MP3特徵值加以辨識，希望此技術能夠抑制網路上P2P非法傳輸的不良風氣。 As MP3 is getting more popular, more P2P services have been emerging on the internet recently. It has been sending shock waves through the music industry as well. For example, Apple iPod has initiated a revolution in the music industry by redefining the portable music experience. However, beyond its success, large amounts of cost were paid for the unauthorized digital audio spreading. In recent years, this problem is getting worse due to the easy download facility provided by the P2P systems. In this paper we try to provide certain techniques to solve this problem. First, packet capturing technique is applied to detect possible MP3 transferring among the P2P systems. Then, based on the MP3 features, the identity of the MP3 songs are recognized and the information about the possible unauthorized MP3 delivery is logged.