On the basis of analyzing features of magnetic characteristics of exposed rock and aeromagnetic anomalies, in combination with the information of local gravity anomalies and previous research achievements in the aspect of regional geology, the authors discussed the relationship between the aeromagnetic anomalies and igneous rocks, interpreted a gravity and magnetic section quantitatively, and then probed into the distribution regularity of the igneous rocks in Yingen-Ejin Banner basin. The results show that magnetic properties of all kinds of rocks are unevenly distributed in Yingen-Ejin Banner basin, and the magnetic properties of the intermediate rocks on the southeast side of Shaomaying and the intermediate rocks and acid rocks near Yingen are stronger, the magnetic properties of the exposed rocks in other areas are weak or close to zero, and the magnetic properties of the basic rocks are weak.