Abstract: Borehole three-component magnetic survey is widely applied in magnetic orebody exploration. Especially in a well prospected area near the existing mine, it is difficult to accurately locate the spatial form of orebody only by limited borehole and ground geophysical data due to deep burial of orebody. To reduce drilling workload and improve drilling effect, borehole three-component magnetic survey has become a common geophysical mean. Based on the study and analysis of three-component magnetic survey data in the borehole near a certain mining area, the paper summarizes the variation law of horizontal and vertical components of magnetic anomaly, and predicts the blind orebodies in and under the well, and infers the burial depth, location, attitude, extension direction and occurrence position of magnetic orebody by combining with the vector characteristics. The method may guide the drilling work effectively.