Increasingly, induction heaters are being widely applied to the energy-saving light industrial equipment. But their electromagnetic radiation’s impact on the environment can’t be ignored. In the paper, several medium frequency induction heaters had been studied under different experimental conditions using E61 electromagnetic field strength analyzer, and as its supplement, the racetrack-coils induction heater had been simulated using ANSYS. According to ICNIRP guidelines, the results show that their radiation is generally in critical state, and magnetic field strength is superstandard in some areas. And countermeasures to the problems are advised.