According to the application trend of internet of things in the power grid，the internet of power transmission and transformation equipments is defined，and the system architecture for the demand of information index，compiling principles and design scheme of equipment identification are proposed by drawing on the coding structure and idea of electronic product code（EPC）and referring to the existing equipment code conventions.Furthermore，some problems such as quantization of the coding scheme and recognition application of identification code are analyzed，and the modularization design method is adopted in constructing the code-identification system and coding system.The structure and function of two systems are expounded at length.Finally the relation between the equipment identification code and the existing power equipment code is investigated.