Abstract: Because of the special geomorphology in areas of shallow overburden, it is difficult to delimit the boundary between mapping units in regional geological mapping. This paper discusses the curve relation between ground magnetic survey and ground gamma spectrometry survey on the basis of the difference in magnetization and radioactive element content for different mapping units. By analyzing the measured profile, the relation between the magnetic anomaly curve and radioactive anomaly curve has been obtained for different mapping units in the Da Hinggan igneous province. This method can apply for delimiting a boundary between mapping units quickly in a shallow overburden area so as to reduce trenching work and abate the work intensity.