The azimuth measurement accuracy of the magnetic compass installed on the shipboard helicopter is not only affected by the magnetic interference of the helicopter itself,but also by the magnetic interference existing on the ship when the shipboard helicopter takes off,lands and flies over the ship at low altitude. In this paper,the working principle of the magnetic compass and the mechanism of azimuth measurement error are discussed,and a feasible method for magnetic interference calibration of the magnetic compass in the shipboard helicopter is proposed. At the same time,the influence of the ship magnetic interference on the azimuth of the magnetic compass when the shipboard helicopter flies over the ship at different azimuth angles and heights is analyzed. It is then verified through MATLAB simulation.