MiniGUI is a bet ter Grap hics User Interface of embedded Linux system , which has lightweight , configurable and portable character . It can be compiled to two different running modes : Mini GUI2Threads mode is designed for simple systems which requires high real2time , like indust ry cont rol apparat us , And Mini GUI2Lite mode is used in multif unctional and complex systems such as PDA. This paper int roduces how to design and implement multi2serial f ull2duplex communication under t he two modes. The difference of listening2p rogram and synchronization problem between t he two MiniGUI modes is pointed out in t he end. Key words : serial port communication ; GUI ;MiniGUI2Threads ;Mini GUI2Lite ;