The utility model relates to a multi -functional USB port converter, its characterized in that comprises USB input interface, functional select switch, USB HUB circuit, RS232 interface converting circuit, RJ45 output interface connection, and its advantage converts USB into polytype interface converting functions such as USB HUB, RS232 standard serial port, RJ45 interface to roll into one for the conversion of different grade type interface can once only realize. Its simple structure, convenient to carry, it is easy and simple to handle.