In order to improve the flexibility of the magnetic contour matching (MAGCOM) algorithm, an iteratively improved contour matching (ICM) method is proposed for geomagnetic navigation. In the coarse matching stage, the search strategy is improved, and the mean absolute difference (MAD) is used as the correlation metric for coarse matching. On the basis of the coarse matching results, the contours are constrained, the search domain is reduced iteratively, and the accumulation of ins errors is restrained. The simulation results show that the positioning error of the algorithm is controlled within 200 m under a certain noise level.