Aeromagnetic survey using helicopter with a fixed receiver is suitable for ore prospecting in local key areas, because the survey method has a low flying height of 100 m, a small sampling interval of about 3 m, a high locating precision of less than 1 m, and a low cost of about 30% of the expense of ground magnetic survey. In this paper, the orecaused anomaly was determined by a comparative analysis of the ore body thickness and the aeromagnetic anomaly and a mutual verification of the forward and inversion calculations. The borehole site was determined by precise inversion of the aeromagnetic anomaly. The effectiveness of the method is verified by the fact that iron ore bodies were discovered in all the three borehole sites deployed by the authors at the depth of the Daye iron mine.