According to power system requirements, a kind of threephase multifunctional harmonic energy meter with radio frequency identification (RFID) interface and general packet radio service (GPRS) communication module was developed. The structure and the working principle of the energy meter were described, and its space electromagnetic interference (EMI), conducted coupling interference, and common impedance coupling interference were analyzed. The EMI propagation paths of energy meter were discussed, and the reliability design scheme of energy meter was proposed. The electromagnetic compatibility (EMC) design method of energy meter such as EMC of switch power, PCB routing, communication interface antiinterference design, the antistatic design and software antiinterference design, were analyzed. The EMC test results of the energy meter were given. The experiment and operating results have shown that the threephase multifunctional harmonic energy meter has better EMC.