In response to the demand for high-current measurement in ultra-high-voltage power transmission line of the State Grid, this paper proposes and develops a current measurement method based on a 3He atomic metastable state optically pumped magnetometer. Firstly, the operating principle of the helium atomic metastable state optically pumped magnetometer is introduced, elucidating its physical basis for non-contact measurement of high currents by detecting the external magnetic field generated by the current. Secondly, a helium atomic metastable state excitation circuit is designed and constructed, employing an efficient RF discharge excitation scheme to stably generate helium atomic metastable states, meeting the requirements for subsequent optical pumping. Finally, an experimental measurement system is established to verify the number density of metastable helium atoms of the helium magnetometer. The experimental results demonstrate that the current stage, the helium atoms could be easily stimulated to the metastable state. This research lays the theoretical and engineering foundation for the development of high-precision quantum current sensors for power grid applications and has significant application prospects.