Abstract: A sensitivity compensation method was proposed for anisotropic magnetoresistive(AMR) sensors based on sensitivity online recognition.An experimental study on this method was carried out with an AMR sensor BKMC-21 developed by University of Science and Technology Beijing.The experimental results show that the magnetic field output of BKMC-21 without sensitivity compensation varies greatly after switching the power supply on.It takes about 30 min to be stable,and during this period the sensitivity variation is over 20%.The magnetic field output of BKMC-21 with sensitivity compensation is stable,and the sensitivity variation is less than 2% after switching the power supply on.It can be concluded that the sensitivity compensation method proposed for AMR sensors based on sensitivity online recognition can effectively solve the sensitivity variation problem of magnetometers.