SERF atomic magnetometer has reached the highest sensitivity of 0.16 fT /Hz1 /2in human’s history.Faraday modulation method is the mainly used method for its detecting.But fluctuation of light intensity due to light current disturbance or environment temperature alteration will lead to inaccuracy of detecting result.To solve this problem

closed-loop atomic magnetometer detecting light stable system is designed.Add light path sub-system and control sub-system

on the basis of Faraday modulation method to carry out closed-loop stable control on detecting light intensity.Through closed-loop control simulation and experiment on random interference

verify the system may effectively restrain light intensity fluctuation caused by various disturbances

improve anti-interference ability by 1.2 %

thus the atomic magnetometer detecting precision is improved.