Currently, the electric power system has not yet conducted current measurement research on weak currents below the milliampere level, leaving a gap in this field. With the development of quantum technology, magnetometers based on atomic spin effects have been widely applied. Spin Exchange Relaxation-Free (SERF) atomic magnetometers have the advantage of high sensitivity, allowing for precise measurement of weak currents compared to traditional current measurement technologies. The document discusses the principles and characteristics of SERF atomic magnetometry, the composition and key technologies of magnetometers, and introduces practical technologies for SERF atomic magnetometers, such as gas cell temperature control technology, laser power frequency locking technology, and miniaturization technology. A small current measurement system has been established based on SERF atomic magnetometers, capable of measuring current strengths ranging from 10 nA to 400 μA, with a linear relationship between current strength and magnetic field response; it can respond in real-time to current signals within 1 Hz-100 Hz, and has good consistency in response at several different frequency points set in the experiment. For the problems encountered during the experiment, further research plans are proposed.