Abstract: By analyzing the experimental results of measuring the stable or changing magnetic field using the pumpprobe rubidium atomic magnetometer and the laser-pumped Mz rubidium atomic magnetometer,we show that it is more scientific to calibrate the sensitivity of atomic magnetometer by power spectral density method,and point out that the optimal sensitivity of the designed atomic magnetometers should not be significantly better than the background magnetic noise of the stable magnetic field.This paper discusses the atomic magnetometer’s range,sensitivity,magnetic field sampling rate,response bandwidth of alternating magnetic field,andproposes some suggestions for weak magnetic field metrology.