The firmware upgrade, which is remotely performed, is an essential function in smart metering or AMI (Advanced Metering Infrastructure). In other words, the AMI software and firmware can be switched for maintaining and improvement without replacement of H/W devices in AMI environment. Also, if number and type of devices are increase, the demand of remote update service will be increased. Through the firmware upgrade service remotely, the electric power corporation may be able to benefit various fields. For example, there are to adapt more easily in many environments, real-time service and to cut maintenance costs. In this paper, we proposed to design an international level FUMS(Firmware Upgrade Management System) which includes requirement function, architecture and protocol related with DCU, Smart Meter.