As the precision of existing method based on sine wave magneto-optically modulated polarized light is low, a new high precision method of passing azimuth with the extremum of original light intensity signal is presented. The model of calculating initial light intensity based on discretional light intensity signal is established. The formula of calculating glancing azimuth in wide-angle range and its implemental project are provided and a new high precision method of calculating azimuth in small-angle range is proposed. Simulation results and system error analysis show that, the system error of the new method in the paper is less than those of the existing methods, and it provides a reference to passing spatial azimuth with higher precision.