The Simple Mail Transfer Protocol (SMTP) based E-mail system is the most popular application in today’s Internet world, but there are many dark clouds at the edge of the sunshiny sky. The most well known two threats are the “ mail SPAM” and the “ mail flooding attack .” Mobile agents (MAs) are software agents that can transport themselves from a client computer to various servers for remote execution. Their mobility, autonomy and distributed intelligence are very friendly to today and tomorrow’s Internet computation. In this paper, we introduce a prototype of the Internet mail transfer and check system based on intelligence mobile agents. This new system model can improve the current simple mail transfer protocol model to defend the mail SPAM and the mail flooding attack. Compatible with the traditionary SMTP is the most important feature of our new model. Finally, we summarize some difficulties for turning this prototype model into practical software. Key words: Mobile Ag...