Abstract: The atomic gas in the optical atomic magnetometry is polarized by laser, and the optical characteristics of the gas is further changed by external magnetic field, when a probing laser passes through the gas, the polarization direction and/or intensity will be modulated. The sensitivity of atom magnetometer is comparable to that of superconducting quantum interference devices while the size and weight of atom magnetometer is much smaller. In this paper the dependence of polarization on collision and relaxation is demonstrated, developments in this area both domestic and abroad are summarized, and lastly application of optical atomic magnetometry for navigation is presented.