The central—south Great Hinggan Magmatic Belt is located in the intersection of Solon—Xar Moron River fault and Nenjiang—Baicheng fault. Large- scale magma activities and mineralization are closely related to deep geological processes in this region. The results from integrated geophysical surveys show that low- velocity, low- resistivity, hot anomalies probably exist in the lower- crust and upper mantle depth in this area. We propose that this low density, low- velocity and high- conductivity layer in the lower crust depth might be the hot fluid caused by mantle upwelling, then it melted the lower crust from heating. Generally, the thick asthenosphere and active thermal events in this region are the key factors which caused the large- scale magmatism and mineralization. We suggest that the strong interactions of the crust and mantle in this region, e.g. the upwelling from asthenosphere and the remelt of lower crust, may cause by the subduction of Paleo- Asian Ocean slab, the collision and collage between the North China craton and the Siberian craton, and the subduction of Pacific Plate starting from Late Mesozoic.