The invention relates to a micro-grid data gateway device and a data converting method. The device includes a main controller, a buffer module and a driver module, wherein the driver module is used to respectively receive micro-grid data by an RS485 interface and an RS232 interface, drive the RS485 interface and the RS232 interface work in full duplex, and transmit received micro-grid data to the main controller through the buffer module. The data converting method comprises: collecting a source protocol data frame data by an Internet to transmit it to the main controller, or collecting the source protocol data frame data by the RS 485 interface or the RS232 interface to transmit it to the main controller through the driver module and the buffer module, performing, by the main controller, a protocol conversion on the source protocol data frame data, and transmitting it to the Internet by Ethernet or to the RS 485 interface and the RS232 interface by the buffer module and the driver module.