Abstract: In order to resolve problems of maintenance and upgrade of embedded products in unattended area,a design scheme of remote update system of ARM software based on TFTP protocol was proposed.The system is mainly composed of LPC2290 micro-controller,DM9000E network card chip,SST39VF1601 NOR FLASH and MT45W4MW16 RAM.It can remotely update application software of ARM micro-controller without operating system by use of bootloader technology and TFTP protocol of Ethernet.The testing result showed that the system can ensure correct transmission and storage of data,and reduce difficulty of upgrade and maintenance of ARM embedded system software greatly.