Abstract: The Middle and Lower Reaches of Yangtze River metallogenic belt is one of the major copper resource bases in China. Yanshanian intermediate-acid magmatic rocks play an important role in the formation of various endogenous metal deposits such as copper, iron and gold. It is of great significance for the study of metallogenic dynamics and deep prospecting to identify and determine the three-dimensional distribution of magmatic rocks, especially concealed rock body. Based on gravity and magnetic three-dimensional physical inversion technique, a three-dimensional model of magnetic susceptibility and density difference in the Middle and Lower Reaches of the Yangtze River is obtained. Then according to the correspondence between physical properties and lithology, the three-dimensional structure of igneous rock body in the area is identified and analyzed. It is speculated that there are five main magmatic activity centers in the area, and the form and trajectory of magma flow are discussed. Finally, according to the three-dimensional distribution characteristics of the magmatic rocks in the Middle and Lower Reaches of the Yangtze River, combined with the regional Moho discontinuity, the isostatic gravity anomaly and the multi-scale edge detection results of the gravity and magnetic, and the regional metallogenic background, five prospecting prospects are predicted. The above results show that the gravity and magnetic three-dimensional inversion technique is an effective means for identifying magmatic rock mass. By analyzing the magnetic susceptibility and density distribution of the inversion, the concealed or semi-concealed rock mass can be identified and delineated. The three-dimensional morphological characteristics of the rock mass can be quantitatively obtained, thus providing indication information for finding metal minerals related to volcanic rocks and intrusive rocks body.